Add docs for RequestCache

Closes #48094

See merge request gitlab-org/gitlab-ce!20064

Update squash_and_merge.md to fix link and description

See merge request gitlab-org/gitlab-ce!20093

(cherry picked from commit b5ea33397eb8d2c874662026b0e36aed7c41dbbc)

Add ip_address to json examples in Runner API docs

Closes #47973

See merge request gitlab-org/gitlab-ce!20092

Git ls files is Gitaly only now

Closes #47893 and gitaly#327

See merge request gitlab-org/gitlab-ce!20088

Moved to the front on the line through: https://gitlab.com/gitlab-org/gitlab-ce/issues/47893

Closes: https://gitlab.com/gitlab-org/gitlab-ce/issues/47893
Closes: https://gitlab.com/gitlab-org/gitaly/issues/327

Unify spec/support/redis/redis_shared_examples.rb

See merge request gitlab-org/gitlab-ce!20074

Document end to end flow for Kubernetes and Auto DevOps

Closes #44455

See merge request gitlab-org/gitlab-ce!19699

[Rails5] Force the `protect_from_forgery` callback run first

Closes #48204

See merge request gitlab-org/gitlab-ce!20055

Unify object_storage_spec.rb with EE

See merge request gitlab-org/gitlab-ce!20069

Unify spec/services/auth/container_registry_authentication_service_spec.rb

See merge request gitlab-org/gitlab-ce!20071

Use expect_next_instance_of to replace expect_any_instance_of

See merge request gitlab-org/gitlab-ce!20072

Show a reCAPTCHA on signin page if custom header is set

Closes #48184

See merge request gitlab-org/gitlab-ce!20076

This will only be displayed if `X-GitLab-Show-Login-Captcha` is set as an HTTP
header.

Retroactively add changelogs

See merge request gitlab-org/gitlab-ce!20079

Enable webpack nodeEnv optimization

See merge request gitlab-org/gitlab-ce!20075

For community contributions, changelogs
should be added to the MR.

Fix diff comment alignment for parallel code additions

Closes #47861

See merge request gitlab-org/gitlab-ce!20006

Move boards modal EmptyState vue component

See merge request gitlab-org/gitlab-ce!20068

Fix multiple active tabs when Crowd or LDAP is in use

Closes #48192

See merge request gitlab-org/gitlab-ce!20049

Unify spec/support/shared_examples/features/project_features_apply_to_issuables_shared_examples.rb

See merge request gitlab-org/gitlab-ce!20073

Allow omnibus to disable sourcemaps in memory constrained environments

See merge request gitlab-org/gitlab-ce!20053

Add `gitlab` chart documentation

See merge request gitlab-org/gitlab-ce!20056

CE: Resolve "Extract EE specific files/lines for project_creator_spec"

See merge request gitlab-org/gitlab-ce!19850

Follow-up to !19808: Split up for-loop initializations

See merge request gitlab-org/gitlab-ce!19915