* upstream/master: (620 commits)
  Added '*.js.es6 gitlab-language=javascript' to .gitattributes
  Fix CI status icon link underline
  Update CHANGELOG after 8.10.1
  Add CHANGELOG
  Add es6 gem
  Instrument Nokogiri parsing methods
  Fix backup restore
  Use project ID in repository cache to prevent stale data from persisting across projects
  Add iid to MR API response
  `WikiPage` should have a slug even when not persisted.
  ES6ify all the things!
  Make fork counter always clickable (!5463)
  Revert "Merge branch '17073-tagscontroller-index-is-terrible-response-time-goes-up-to-5-…"
  Fix CHANGELOG
  Add spec for dashes in paths
  Fix Error 500 when creating Wiki pages with hyphens or spaces
  Add links to the real markdown.md file for all GFM examples
  Remove magic comments from Ruby files (!5456)
  Ignore invalid trusted proxies in X-Forwarded-For header
  remove search_id for label dropdown filter
  ...