Prepare for zero downtime migrations

See merge request !9976

Use preload to avoid Rails using JOIN

See merge request !10666

Reset New branch button when issue state changes

Closes #21292

See merge request !5962

Add link to environments on kubernetes.md

See merge request !10555

Improve webpack-dev-server compatibility with non-localhost setups.

Closes #27729

See merge request !10604

Fixes https://sentry.gitlap.com/gitlab/gitlabcom/issues/26786/

Fix filtered search input width for IE

Closes #30856

See merge request !10662

Add auth to topics page

See merge request !10643

Fixed missing capitalisation on buttons

See merge request !10631

Starting with GitLab 9.1.0 we will no longer allow downtime migrations
unless absolutely necessary. This commit updates the various developer
guides and adds code that is necessary to make zero downtime migrations
less painful.

Fixed random failures with Poll spec

Closes #30824

See merge request !10654

Remove heading and trailing spaces from label's color and title

See merge request !10603

Include CONTRIBUTING.md file when importing .gitlab-ci.yml templates

See merge request !10653

Improve the testing documentation

Closes #29499 and #29623

See merge request !10161

Set user contribution calendar `overflow-x: scroll` more precisely

Closes #30738

See merge request !10636

removes redundant code from database.rb

Closes #29056

See merge request !10583

Improve discussion_comments_spec perf

See merge request !10648

Fix grammar

See merge request !10639

Resolve "Update Pipelines documentation"

Closes #27755

See merge request !10600

Correctly waits for requests to finish before testing anything.
Previously it was waiting for a set amount of time which could possibly
cause failures dependant on how quickly these execute

Stops any polling requests once done so that the error callback doesn't
get called with a 404

Closes #30824

Return nil as coverage instead of a File object

See merge request !10633

Let uses hide verbose output by default

See merge request !10650

[ci skip]

Fix outdated 'Admin area' link label in GitLab QA

Closes gitlab-qa#41

See merge request !10646

Api fix build events rename to Job events

Closes #30412

See merge request !10586

Use gRPC 1.2.2

Closes #30766

See merge request !10589

Given a valid pipeline job, and a regex which wouldn't match to a jobs
trace, the stream of the trace would return the File object. This was
not the case when it matched a value, as that would have been return
from the block.

Now the `extract_coverage` method returns `nil` if no match was found.

Hide new subgroup button if user has no permission to create one

Closes #30139

See merge request !10627

Setup and run a Gitaly server for testing if GitalyClient is enabled

See merge request !10298

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

Fix issue's note cache expiration after delete

Closes #30457

See merge request !10461