Merge branch 'master' into 29575-polling

* master: (71 commits)
  Merge branch 'render-json-leak' into 'security'
  Merge branch 'ssrf' into 'security'
  Merge branch 'ssrf' into 'security'
  Merge branch 'fix-links-target-blank' into 'security'
  Merge branch '28058-hide-emails-in-atom-feeds' into 'security'
  Fix karma test
  Reset filters after click
  Handle Route#name being nil after an update
  Only add frontend code coverage instrumentation when generating coverage report
  fix recompile assets step in 9.0 upgrade guide to use yarn
  Undo explicit conversion to Integer
  Make level_value accept string integers
  Make feature spec more robust
  Removed d3.js from the main application.js bundle
  Update css to be nice and tidy.
  add an index to the ghost column
  Improve rename projects migration
  Add additional check for when inputContainer does not exist
  Make the v3_to_v4.md more consistent
  Fix input token spacing
  ...