Prefer `flat_map` over `map` + `flatten`

See merge request gitlab-org/gitlab-ce!31144

Convert several occurrences of `map` + `flatten` to
`flat_map` where applicable.

Prefer `flat_map` over `map` + `flatten`

See merge request gitlab-org/gitlab-ee!14661

Add development documentation on label filtering

Closes #49651

See merge request gitlab-org/gitlab-ce!30741

Update dependency @gitlab/ui to ^5.9.0

See merge request gitlab-org/gitlab-ce!31153

The GitLab UI update changed the spinner selector from `spinner` to
`gl-spinner`, so we need to update it, so that our tests won't fail.

Update dependency @gitlab/ui to ^5.9.0

See merge request gitlab-org/gitlab-ee!14853

The GitLab UI update changed the spinner selector from `spinner` to
`gl-spinner`, so we need to update it, so that our tests won't fail.

Extract Auto DevOps deploy functions in a base image

Closes #50286

See merge request gitlab-org/gitlab-ce!30404

Adds event enum column to DesignsVersions join table

See merge request gitlab-org/gitlab-ce!30745

Support indentation in the markdown editor

Closes #25070

See merge request gitlab-org/gitlab-ce!28914

It will be hooked up to the markdown editor later

Ensure Warden triggers after_authentication callback

See merge request gitlab-org/gitlab-ce!31138

By not triggering the callback:
- ActiveSession lookup keys are not cleaned
- Devise also misses its hook related to session cleanup

CE port of "Stablize editing scope label spec - retry if dropdown is not visible"

See merge request gitlab-org/gitlab-ce!31145

Stablize editing scope label spec - retry if dropdown is not visible

Closes gitlab-org/quality/nightly#117

See merge request gitlab-org/gitlab-ee!14841

Respect alt email when sending group access notifications

See merge request gitlab-org/gitlab-ce!31089

When sending access granted/rejected emails we should also respect
custom emails set for groups/sub-groups

Feature test for gfm embedding metrics

See merge request gitlab-org/gitlab-ce!30621

Add points how to prepare for database reviews

Closes #65126

See merge request gitlab-org/gitlab-ce!31158

CI Docs update for Marketing

See merge request gitlab-org/gitlab-ce!30440

Update README.md - add CTA to watch Mastering CI/CD webcast and 5 teams that made the switch to GitLab CI/CD article

Add docs for template field in prometheus alerts

See merge request gitlab-org/gitlab-ce!30900

(EE Port) Change link to relative to match CE MR

See merge request gitlab-org/gitlab-ee!14850

Add Troubleshooting section for Merge Train documentation

Closes #64948

See merge request gitlab-org/gitlab-ce!31033