Releast v1.147.0

[tiftran]

Welcome Release Captain! ⛵️

• [x] Assign this issue to yourself
• [x] Approve and merge all open dependabot/renovate/pyup PRs by adding a bors merge comment to the PR.
• [x] Pull master on a local checkout of Normandy
• [x] Ensure all linting and tests pass with docker: make check
• [x] git tag v1.147.0; git push --tags
  • pushing a tag triggers a stage deployment automatically
• [x] Generate release notes:
  • ./bin/generate_deploy_bug.py v1.146.1 v1.147.0
  • on mac: python3 ./bin/generate_deploy_bug.py v1.146.1 v1.147.0
• [x] Create release entry in https://github.com/mozilla/normandy/releases/ with content copied from release notes
• [x] in #normandy, write: @here deploying normandy v1.147.0 to stage <link to release entry>
• [x] Verify that stage loads with v1.147.0
  • [x] Wait for delivery notifications in #delivery-notifications to indicate that stage is being built and deployed
  • [x] Verify that the stage __version__ endpoint shows the new version number
  • [ ] File Bugzilla Release Bug with content copied from release notes
• [x] Add QA :cmuresan as QA contact on the bugzilla ticket
• [x] Add release bug to comments in this issue~~
• [x] Await QA green sign off
  • if there was a bug found, generate a point release, push the new tag and let QA know to test again.
• [x] @sven please deploy normandy v1.143.X to prod <bugzilla link> in #normandy where X is last point release and is the link to the bugzilla ticket created above
• [x] Verify that the __version__ endpoint shows the correct version number
• [x] Fetch https://normandy.cdn.mozilla.net/api/v3/recipe/ to verify it returns a 200