Merge tag 'release-5.0.4' into release-5.0-stable

* tag 'release-5.0.4':
  Bumped version to 5.0.4
  Bug 1438593: Release notes for Bugzilla 5.0.4 r/a=dylan
  Bug 1433400 (CVE-2018-5123) Prevent cross-site image requests from leaking contents of certain fields due to regex search r=jfearn,a=dylan
  Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=1427623 by setting (#57)
  Significant update to jb2bz.py. (#58)
  Bug 1301887 - File::Slurp triggers warnings on perl 5.24 (#53)
  Bug 1398100 - tiny tweaks to release notes
  Revert "Bug 1306534 - Crash when pasting UTF8 text as an attachment"
  Bug 1310728 - editflagtypes.cgi crashes when classifications are enabled and the user hasn't global editcomponents privs r/a=dkl
  Bug 1306534 - Crash when pasting UTF8 text as an attachment
  nit: wrong method call in Bugzilla::Migrate
  Bug 1300437 - DateTime::TimeZone::offset_as_string called incorrectly (#19)
  Bug 1303702 - bug history table 'when' column shows 00:00 only using sqlite
  - New CI docker image for testing
  Bug 1292510 - replace references to git.mozilla.org with references to github. r=dylan
  Fix the default API URL
  Bug 1269266 - API links for Bugzilla 5+ not working anymore
  Bug 1273846 - Checksetup fails to update chart storage during pre-3.6 -> 5.0 upgrade r/a=dkl
  Bumped version post-release