Union examples in event spec for speed up

## What does this MR do?

Increase tests speed for event model.

## Why was this MR needed?

This change saves about 15-18 seconds.

See merge request !6821

Update to gitlab-shell 3.6.6

## What does this MR do?

This updates gitlab-shell to version 3.6.6

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [ ] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

See merge request !6830

Document Capybara errors from es6 in es5 file.

## What does this MR do?

Documents an error that I've banged my head against twice now. 

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

The greater good. 

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

See merge request !6836

Fix step number and token param in URL example. Fix gitlab-rails command code formatting.



See merge request !6791

Improve merge request versions compare logic

## What does this MR do?

Changes the way how we compare between for merge request versions 

## Are there points in the code the reviewer needs to double check?

no 

## Why was this MR needed?

So when I squash+rebase my commit I can get more accurate diff on what changed between versions

## Screenshots (if relevant)

in discussion (below)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] ~~[Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~
- [ ] ~~API support added~~
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/22368, https://gitlab.com/gitlab-org/gitlab-ce/issues/22721

See merge request !6589

API: Version information

## What does this MR do?

Adds a new endpoint to retrieve the version information.

## Why was this MR needed?

Clients can now use this information to enable/disable certain API features depending on the version.  

## What are the relevant issue numbers?

Closes #22608, https://gitlab.com/gitlab-org/gitlab-ce/issues/23148

See merge request !6822

Update health_check gem to `~> 2.2.0`

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/22278

See merge request !6835

Add a bundle check step to ensure dependencies are correct

This should help prevent merge issues in the future, which caused !6814 to be needed.

See merge request !6815

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/22278

Resolve "Move `/licenses` api endpoint to `/templates/licenses`"

## What does this MR do?

It moves the `/licenses`, `/gitignores` and `/gitlab_ci_ymls` API endpoints under the `/templates` namespace

## Why was this MR needed?

In EE we now have somewhat ambiguous API endpoints. `/license` refers to the EE license while `/licenses` (plural) refers to license templates. @DouweM mentioned that we're adding .gitignore templates in #14106 so it may make sense to add a /templates namespace. Then, move the /license templates endpoint to be underneath, along with .gitignore endpoints. 

Closes #17541

See merge request !5717

This reverts merge request !6730

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Added documentation chapter for Git attributes

See https://gitlab.com/gitlab-org/gitlab_git/issues/28 for more information.

See merge request !6826

Use activerecord_sane_schema_dumper

## What does this MR do?

> `ActiveRecord::SaneSchemaDumper` modifies the behavior of Rails’ `ActiveRecord::SchemaDumper` so that the generated `db/schema.rb` file doesn’t contain any useless/harmful whitespace column alignment.

## Why was this MR needed?

To reduce potential conflicts in `db/schema.rb` (see https://gitlab.com/gitlab-org/gitlab-ee/issues/715).

See merge request !6827

As discussed in https://gitlab.com/gitlab-org/gitlab_git/issues/28 we'll
need to clearly document the need for .gitattributes files being encoded
using UTF-8.

[ci skip]

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Rémy Coutable <remy@rymai.me>

This should help prevent merge issues in the future, which caused !6814
to be needed.

API: New /users/:id/events endpoint

## What does this MR do?

If add a new `/users/:id/events` endpoint to retrieve a user's contribution events. The events returned are filtered so that only the events for projects that the current user can see are returned (similarly to what we do at the controller level).

## Why was this MR needed?

Because it's a nice feature to calculate leaderboards, for instance for #17815.

## What are the relevant issue numbers?

Closes #20866.

See merge request !6771

Add disabled delete button to protected branches

## What does this MR do?
Add's a disabled CSS style for the delete button on protected branches instead of hiding the button

## What are the relevant issue numbers?
Closes #22358

See merge request !6439

Speed up specs for GET /projects/:id/events

## What does this MR do?

Just groups some expectations into a single `it` block. Reduce this particular tests block time by half.

See merge request !6778

Removes inconsistency regarding tagging immediately as merged once you create a …

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?


Closes #20708

See merge request !6408

The /licenses, /gitignores and /gitlab_ci_ymls endpoints are now also
available under a new /templates namespace. Old endpoints will be
deprecated when GitLab 9.0.0 is released.

Added 'Download' button to snippet view

## What does this MR do?

Adds a `Download` button above a snippet.

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

Requested in #22811 

## Screenshots (if relevant)

![image](/uploads/59b67aa02cc601c08a18fd60c37797ed/image.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Closes #22811

See merge request !6720

Add CHANGELOG entry for 8.12.6



See merge request !6816