Resolve "CE documentation is not CommonMark compliant"

Closes #50695

See merge request gitlab-org/gitlab-ce!21385

Handled exception during file upload

See merge request gitlab-org/gitlab-ce!21528

Fix closing issue default pattern

Closes #51085

See merge request gitlab-org/gitlab-ce!21531

* (Suf)fix #51085 :-)
Signed-off-by: Samuele Kaplun <kaplun@protonmail.com>

Resolve "Remove usage ping payload from Cohorts, add to Settings"

Closes #50567

See merge request gitlab-org/gitlab-ce!21343

Recognize 'UNLICENSE' license files

See merge request gitlab-org/gitlab-ce!21508

Add terminal path to job API response

Closes #51117

See merge request gitlab-org/gitlab-ce!21537

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

closes #51117

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