message: trigger workflow runs on bor's "staging" branch
  I think:
  trying is for bors try
  staging is for bors r+
diff: @@ -2,9 +2,9 @@ name: CI
  on:
  push:
  - branches: [ master, trying ]
  + branches: [ master, trying, staging ]
  pull_request:
  - branches: [ master, trying ]
  + branches: [ master, trying, staging ]
  # Allows you to run this workflow manually from the Actions tab
  workflow_dispatch:
  