Make MR diff file filter input Clear button functional

Closes #51092

See merge request gitlab-org/gitlab-ce!21556

Add git_v2 flag to GitalyClient

See merge request gitlab-org/gitlab-ce!21520

Fix attachments not displaying inline with Google Cloud Storage

Closes #49957

See merge request gitlab-org/gitlab-ce!21265

Custom Action support

See merge request gitlab-org/gitlab-ce!21034

Port changes for CODEOWNERS to CE

See merge request gitlab-org/gitlab-ce!21309

Enable Kubernetes RBAC for GitLab Managed Apps for existing clusters

See merge request gitlab-org/gitlab-ce!21127

Fix usage statistics typo documentation

See merge request gitlab-org/gitlab-ce!21555

Resolve "Update presentation for SSO providers on log in page"

Closes #44943

See merge request gitlab-org/gitlab-ce!21233

Explicit hashed path check for trace, prevents background migration from…

See merge request gitlab-org/gitlab-ce!21533

- Use proper HTTP codes for /api/v4/allowed response
- CustomAction support

- if #check_custom_action!(cmd) returns something, return from #check()
- now returns :Gitlab::GitAccessResult::Success.new instead of true

Add User-Agent to production_json.log

See merge request gitlab-org/gitlab-ce!21546

Update user markdown documentation for CommonMark

See merge request gitlab-org/gitlab-ce!21509

Enable CommonMark for files and wikis

See merge request gitlab-org/gitlab-ce!21228

Fix LineBreakAroundConditionalBlock cop for a conditional after rescue

See merge request gitlab-org/gitlab-ce!21535

Resolve "Improve project overview UI"

Closes #44704

See merge request gitlab-org/gitlab-ce!20536

This ports the changes for the CODEOWNERS feature to CE:
- It adds the CODEOWNERS file.
- It adds the mention of the `with-codeowners` branch in TestEnv

Upgraded Monaco editor version

See merge request gitlab-org/gitlab-ce!21526

CE backport of changes that introduce custom instance-level templates to EE

See merge request gitlab-org/gitlab-ce!21530

There were several issues:

1. With Google Cloud Storage, we can't override the Content-Type with
Response-Content-Type once it is set.  Setting the value to
`application/octet-stream` doesn't buy us anything. GCS defaults to
`application/octet-stream`, and AWS uses `binary/octet-stream`. Just remove
this `Content-Type` when we upload new files.

2. CarrierWave and fog-google need to support query parameters:
https://github.com/fog/fog-google/pull/409/files, https://github.com/carrierwaveuploader/carrierwave/pull/2332/files.
CarrierWave has been monkey-patched until an official release.

3. Workhorse also needs to remove the Content-Type header in the request
(https://gitlab.com/gitlab-org/gitlab-workhorse/blob/ef80978ff89e628c8eeb66556720e30587d3deb6/internal/objectstore/object.go#L66),
or we'll get a 403 error when uploading due to signed URLs not matching the headers.
Upgrading to Workhorse 6.1.0 for https://gitlab.com/gitlab-org/gitlab-workhorse/merge_requests/297
will make Workhorse use the headers that are used by Rails.

Closes #49957

Bump browser gem to v2.5.3

See merge request gitlab-org/gitlab-ce!21547

Full list of changes: https://github.com/fnando/browser/blob/master/CHANGELOG.md

This will help production gain more visibility which browsers may be
having issues.

Add route information to lograge structured logging for API logs

Closes #50993

See merge request gitlab-org/gitlab-ce!21487

Fix documentation on upgrading when using a Helm chart

See merge request gitlab-org/gitlab-ce!21539

Add support for advanced CI/CD config extension with `extends:`

Closes gitlab-ee#6136

See merge request gitlab-org/gitlab-ce!21243

Fix multipart error on rails reload

See merge request gitlab-org/gitlab-ce!21540

remove comma

See merge request gitlab-org/gitlab-ce!21536