Bump Hashie to 3.5.5 and omniauth to 1.4.2 to eliminate warning noise

Closes #28595

See merge request !9534

Add quotes to coverage pattern

See merge request !9545

Adds backoff algo from EE to CE

See merge request !9517

Update Vue to v2.1

See merge request !9386

Add clearer placeholders and channel definition for Mattermost and Slack notifications services

See merge request !9139

[ci skip]

Closes #28595

Make Git history follow renames again by performing the --skip in Ruby

Closes #23062

See merge request !9314

Update users.md

See merge request !9475

Consistently create, update, and delete files, taking CRLF settings into account

See merge request !9207

Adds confirmation for cancel button

Closes #28419

See merge request !9519

Removes label from previous list

Closes #28484

See merge request !9418

Remove require.context from application.js

See merge request !9491

Added user-callouts

Closes #27269

See merge request !9249

Remove require.context from profile_bundle

See merge request !9492

Remove require.context from protected_branches_bundle

See merge request !9493

Remove require.context from snippet_bundle

See merge request !9494

Remove require.context from users_bundle

See merge request !9496

Removed jQuery UI highlight & autocomplete

See merge request !8420

Also removed eslint disabled rules

Resolve "Renamed file tooltip contains html"

Closes #28366

See merge request !9374

Refactor graphs bundle to ES module syntax

See merge request !9502

Issue boards card template in JS

See merge request !9477

fixes line number copy issue for unfolded parallel view diff

Closes #28367

See merge request !9365

Fix typo in auth0.md doc

Closes #27847

See merge request !9059

Deleting a user shouldn't delete associated issues.

Closes #12726

See merge request !7393