Add auto-cancel for pending pipelines on branch, if they are not HEAD

See merge request !9362

* upstream/master: (58 commits)
  Fix icon name error
  Rewrite system note helper
  Change edit icon
  Leave icon area blank if legacy note; remove diamond icon
  Fix positioning of note icons
  Fix newline errors
  Add remaining system note icons
  Add system notes icon helper; add icons
  Fixed specs Updated JS that was causing the hints to appear & then disappear
  Update tests
  Fix broken spinach test
  Reuse code
  Improve shortcuts code
  Adds ShortcutsDashboardNavigation to globals comment since its a global variable
  Fix shortcut specs
  Reorganize shortcut help menu
  Change todos shortcut to shift
  Change shortcuts
  Switch global shortcuts to shift; reuse key styles from help menu
  Map bindings to lowercase letters; only show key bindings when using keyboard shortcut
  ...

Enable caching in the Etag::Middleware and when a pipeline changes
status, expire the cache for the project pipelines path.

* upstream/master: (197 commits)
  Add text to break up diagrams
  Implement review comments from @DouweM for !10467.
  Fix rubocop offence
  Linking to edit file directly
  Optimise trace handling code to use streaming instead of full read
  Use config.toml to configure Gitaly
  Fix indexes in container repositories table
  Recent search history for issues
  Fix rubocop
  Use change direction in spec
  Use be_pending
  Improve trigger_schedule.rb
  Implement a offset calculation on cron_parser_spec
  Clean up trigger_schedule_worker_spec.rb
  Improve instantiate recursion in cron_parser.rb
  Fix unnecessary changes in schema.rb
  Add empty line in cron_parser.rb
  Use parenthesis for respond_to :ref
  Define next_time as let in trigger_schedule_spec
  Remove next_run_at: nil from trigger_schedule_spec
  ...