Milestoneish#issues_visible_to_user caches only the ActiveRecord relation,
not the actual result.
Introduce Milestoneish#total_issues_count that relies on the cached method
Milestoneish#count_issues_by_state to reduce the number of queries.

Resolve "Add link to Branches page help text?"

Closes #26129

See merge request !8377

Pipelines Vue

See merge request !7196

Validate label's title length

See merge request !5767

Update the gitlab-markup gem to the version `1.5.1`

See merge request !8509

Remove the project_authorizations.id column

See merge request !8479

Change CI template linter textarea with Ace Editor

Closes #24179 and #19701

See merge request !8452

Use #parts instead of #part to read all the parts of the Message.

Closes #26463

See merge request !8507

Make play button on Pipelines page accessible via keyboard

See merge request !8496

Resolve "Certain buttons are not accessible via the keyboard (Web)"

Closes #26238

See merge request !8469

View spec for Ryancharris/gitlab milestone counter number with delimiter

See merge request !8482

Made download artifacts button accessible via keyboard

Closes #26446

See merge request !8493

Looks like I was accidentally using #part which was adding an extra
empty Mime section

Fix Double Spaced CI Log

Closes #19086

See merge request !8349

Make successful pipeline emails off for watchers

Closes #24845

See merge request !8176

Log LDAP blocking/unblocking events to application log

See merge request !8042

Don't instrument 405 Grape calls

Closes #26051

See merge request !8445

Added update guides for 8.16RC1

See merge request !8502

+ add test for label.title length validation

Re-order update steps in the 8.14 -> 8.15 upgrade guide

Closes #26014

See merge request !8287

Record and show last used date of SSH Keys

See merge request !8113

Fix broken url on group avatar

Closes #26452

See merge request !8464

Fixes #26051.
Signed-off-by: Rémy Coutable <remy@rymai.me>

1. Gems need to be installed before we can run the
  gitlab:workhorse:install task
1. Update gitlab-shell after gitlab-workhorse since it's a manual step
  that needs to be done in `/home/git/gitlab-shell`
Signed-off-by: Rémy Coutable <remy@rymai.me>

Addresses: Issue #13810

1. Adds a last_used_at attribute to the Key table/model
2. Update a key's last_used_at whenever it gets used
3. Display how long ago an ssh key was last used

This column used to be a 32 bits integer, allowing for only a maximum of
2 147 483 647 rows. Given enough users one can hit this limit pretty
quickly, as was the case for GitLab.com.

Changing this type to bigint (= 64 bits) would give us more space, but
we'd eventually hit the same limit given enough users and projects. A
much more sustainable solution is to simply drop the "id" column.

There were only 2 lines of code depending on this column being present,
and neither truly required it to be present. Instead the code now uses
the "project_id" column combined with the "user_id" column. This means
that instead of something like this:

    DELETE FROM project_authorizations
    WHERE user_id = X
    AND id = Y;

We now run the following when removing rows:

    DELETE FROM project_authorizations
    WHERE user_id = X
    AND project_id = Y;

Since both user_id and project_id are indexed this should not slow down
the DELETE query.

This commit also removes the "dependent: destroy" clause from the
"project_authorizations" relation in the User and Project models.
Keeping this prevents Rails from being able to remove data as it relies
on an "id" column being present. Since the "project_authorizations"
table has proper foreign keys set up (with cascading removals) we don't
need to depend on any Rails logic.