message: Fix unexpected coverage diffs for PRs that aren't up to date
diff: @@ -12,6 +12,11 @@ jobs:
  steps:
  - name: Checkout code
  uses: actions/checkout@v2
  + with:
  + # If this is a pull request, make sure we check out its head rather than the
  + # automatically generated merge commit, so that the coverage diff excludes
  + # unrelated changes in the base branch
  + ref: ${{ github.event.type == 'PullRequestEvent' && github.event.pull_request.head.sha || '' }}
  - name: Yarn cache
  uses: c-hive/gha-yarn-cache@v2
  