Test against PG9 by default, PG11 in master, and PG10 nightly

Closes #215053

See merge request gitlab-org/gitlab!30293

Refactor count queries in Projects::EnvironmentsController

See merge request gitlab-org/gitlab!30073

create subgroup without create project permission

See merge request gitlab-org/gitlab!28309

Remove mocked methods from dashboard spec

See merge request gitlab-org/gitlab!30486

Add validate yml to advanced troubleshooting

Closes gitlab-com/support/docs#66

See merge request gitlab-org/gitlab!30074

refactor: add icon for `.prettierignore`

See merge request gitlab-org/gitlab!30517

Added "Introduced in version" section to push_options.md

See merge request gitlab-org/gitlab!30436

Improve more Rake task topics

See merge request gitlab-org/gitlab!30456

Limit commits used in signature updating

Closes #214780

See merge request gitlab-org/gitlab!30563

Include improvements suggested by @xlgmokha

See merge request gitlab-org/gitlab!30409

Clean up job_artifacts after review

See merge request gitlab-org/gitlab!30567

Move extra includes examples out of reference

See merge request gitlab-org/gitlab!30460

Docs: tone and style revisions, AutoDevops page

Closes #213163

See merge request gitlab-org/gitlab!30540

Cleans up the latter half of the Auto DevOps page for tone and style.

Use microseconds precision for timings log

See merge request gitlab-org/gitlab!30417

Move sections higher up on page, clean up
Vale warnings, etc.

Docs: tone and style revisions to Stages page

See merge request gitlab-org/gitlab!30535

Docs: tone and style revisions to stages page

Closes #215798

See merge request gitlab-org/gitlab!30518

Update instructions to view self-managed subscription

See merge request gitlab-org/gitlab!30515

Revert "Merge branch 'sh-update-grape-gem' into 'master'"

See merge request gitlab-org/gitlab!30561

Upgrade Nokogiri to v1.10.9

See merge request gitlab-org/gitlab!30435

Move artifact reports from yaml reference to job artifacts doc

See merge request gitlab-org/gitlab!30465

Artifact reports details did not need to be in the
yaml reference.

Add dast_jobs to docs for tracked information

See merge request gitlab-org/gitlab!30386

Prior to the addition of x509 signature support, we only processed the
last 100 commits, so this reverts to our previous behavior by limiting
the number of commits considered to those returned by `#limited_commits`

This reverts merge request !27276

Add batch_column_name option to rename_column_concurrently

See merge request gitlab-org/gitlab!30106

Docs - Explain remediations better

See merge request gitlab-org/gitlab!30307

Add search by name to Image Repository

See merge request gitlab-org/gitlab!29763

- project / registry
- group / registry
- unit tests
Co-authored-by: Nick Kipling <nkipling@gitlab.com>
Co-authored-by: Steve Abrams <sabrams@gitlab.com>

Re-Fix final_delay exception in MigrationHelpers

See merge request gitlab-org/gitlab!30549

Add icon to subepics issues when filtering by epic

See merge request gitlab-org/gitlab!27212

If the issues are being filtered by epic_id, any issueable with a
different epic_id is considered a child, so an icon indicator is shown
with information on a tooltip.