* master: (40 commits)
  Use GitLab Pages v0.4.2
  Do not reprocess actions when user retries pipeline
  Add specs for extended status for manual actions
  Refine inheritance model of extended CI/CD statuses
  Introduce generic manual action extended status class
  Check ability to update build on the API resource
  Require build to be present in the controller
  Authorize build update on per object basis
  Use update build policy instead of new play policy
  Improve environment policy class
  Rephrase documentation for protected actions feature
  Improve code style related to protected actions
  Add changelog entry for external env URL btn fix
  Hide environment external URL button if not defined
  Fix builds controller spec related to protected actions
  Fix environment policy class name in specs
  Add Changelog entry for protected manual actions
  Document protected manual actions feature
  Improve specs for jobs API regarding manual actions
  Fix Rubocop offense in environments policy class
  ...