Improve project build time setting validation

Closes #44443

See merge request gitlab-org/gitlab-ce!20591

Fix RSS button interaction on Dashboard, Project and Group activities

Closes #48894

See merge request gitlab-org/gitlab-ce!20549

Avoid process deadlock in popen by consuming input pipes

Closes gitlab-ee#6895

See merge request gitlab-org/gitlab-ce!20600

Add missing `CI_COMMIT_BEFORE_SHA` predefined variable

Closes #43365

See merge request gitlab-org/gitlab-ce!20594

Open pipeline list panel when clicking CI icon in Web IDE

Closes #47843

See merge request gitlab-org/gitlab-ce!20516

Update docs board features tier

See merge request gitlab-org/gitlab-ce!20602

Make more ref RPC's mandatory

Closes gitaly#526, gitaly#965, gitaly#476, and gitaly#474

See merge request gitlab-org/gitlab-ce!20592

A process that spews a lot of output to stderr or stdout could stall out
due to the pipe buffer being full. As described in https://bugs.ruby-lang.org/issues/9082,
we can use the trick used in Ruby's capture3 function to read the pipes in separate
threads.

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/6895

Upgrade grape-path-helpers to 1.0.6

See merge request gitlab-org/gitlab-ce!20601

Polish severity level facets further

See merge request gitlab-org/gitlab-ce!20572

Include Vue files without tests in coverage report

Closes #48912

See merge request gitlab-org/gitlab-ce!20431

Remove healthchecks from prometheus endpoint

Closes #49112

See merge request gitlab-org/gitlab-ce!20565

Backport mr widget changes from EE

See merge request gitlab-org/gitlab-ce!20598

i18n: externalize strings from 'app/views/admin/groups'

See merge request gitlab-org/gitlab-ce!19924

Resolve "QA: False failure on QA test "Push to protected branch when allowed" during staging failover rehearsal"

Closes #48241

See merge request gitlab-org/gitlab-ce!20561

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

Allow to toggle notifications for issues due soon

Closes #47709

See merge request gitlab-org/gitlab-ce!20530

Signed-off-by: Tao Wang <twang2218@gmail.com>

Vuex test helper improvements

Closes #44912, #44919, and #44920

See merge request gitlab-org/gitlab-ce!20513

[QA] Fix duplicate year in namespace name

See merge request gitlab-org/gitlab-ce!20581

Resolve "Installing helm tiller sometimes fails with no api token found"

Closes #49139

See merge request gitlab-org/gitlab-ce!20580

Fix performance problem of tags query

Closes gitlab-com/infrastructure#4550

See merge request gitlab-org/gitlab-ce!20555

Update CONTRIBUTING.md to port Contribution Flow section from EE doc

See merge request gitlab-org/gitlab-ce!20546

Resolve "Improve performance of MR Changes tab: reduce event listeners on scroll event"

Closes #48639 and #48789

See merge request gitlab-org/gitlab-ce!20558