* master: (30 commits)
  Docs: Pages - clean up articles
  Only use features for events
  Put all event metrics exposed to prometheus behind a feature flag
  Add version which LFS lock was introduced
  Remove unecessary validate: true from belongs_to :project
  fix broken specs
  remove common_d3 bundle
  remove graphs_show webpack bundle
  Chart.html.haml refactor
  Remove extraneous tests from Issues API spec
  [GH Import] Create an empty wiki if wiki import failed
  Resolve "group request membership mail with too long list of "To:""
  Add changelog entry
  Fix single digit value clipping
  specify date format
  Increase feature flag cache TTL to one hour
  Convert Gitaly commit parent IDs to array as early as possible
  Clarify changelog for squash encoding fix
  Avoid slow File Lock checks when not used
  Fix squash rebase not working when diff contained encoded data
  ...

Docs: Pages - clean up articles

See merge request gitlab-org/gitlab-ce!17188

Fix for sidekiq metrics set cardinality growing unbounded

Closes #43424

See merge request gitlab-org/gitlab-ce!17235

Merge branch '43376-follow-up-from-docs-update-all-articles-with-the-new-layout-metadata-from-the-frontmatter' into 'master'

Resolve "Follow-up from "Docs: Update all articles with the new layout (metadata from the frontmatter)""

Closes #43376

See merge request gitlab-org/gitlab-ce!17214

Add version which LFS lock was introduced

See merge request gitlab-org/gitlab-ce!17233

Move spinach project network graph tests to RSpec

See merge request gitlab-org/gitlab-ce!17171

Remove unecessary validate: true from belongs_to :project

See merge request gitlab-org/gitlab-ce!17166

Remove graphs_show.js webpack bundle

See merge request gitlab-org/gitlab-ce!17194

This does not seem to serve any clear purpose and causes other issues (see https://gitlab.com/gitlab-org/gitlab-ce/issues/43196#note_59275652)

Remove extraneous tests from Issues API spec

Closes #25201

See merge request gitlab-org/gitlab-ce!17222

Update two links in the changelog developer docs

See merge request gitlab-org/gitlab-ce!17220

Chart.html.haml refactor

See merge request gitlab-org/gitlab-ce!16897

These were all testing an implementation detail of
`Issues::UpdateService` which is already well-tested and doesn't need to
be re-tested here.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/25201

[GH Import] Create an empty wiki if wiki import failed

Closes #43020

See merge request gitlab-org/gitlab-ce!17112

Resolve "group request membership mail with too long list of "To:""

Closes #42274

See merge request gitlab-org/gitlab-ce!17121

Fix single digit value clipping for stacked progress bar

Closes gitlab-ee#4864

See merge request gitlab-org/gitlab-ce!17217

Avoid slow File Lock checks when not used

Closes #43339

See merge request gitlab-org/gitlab-ce!17140

Increase feature flag cache TTL to one hour

Closes #40854

See merge request gitlab-org/gitlab-ce!17213

Fix and simplify end-to-end tests for secret variables

Closes gitlab-qa#190

See merge request gitlab-org/gitlab-ce!17173

Updates components to use a slot to allow to reuse the clipboard button
Adds tests

Flipper already takes care of flushing cache entries when
enabling/disabling features so it should be safe to increase the TTL.
This in turn should drastically reduce the number of Flipper queries
executed.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/40854

Resolve "Double closing system  notes when closing issue with Merge Request"

Closes #32546 and #32564

See merge request gitlab-org/gitlab-ce!17035