Fix concurrency group
The previous one only works for PRs, but not for post-merge, since
`head_ref` is not set in that case.
@@ -8,7 +8,7 @@ on:
# See https://docs.github.com/en/actions/learn-github-actions/workflow-syntax-for-github-actions#example-using-concurrency-to-cancel-any-in-progress-job-or-run
concurrency:
- group: ${{ github.head_ref }}
+ group: ${{ github.head_ref || github.ref }}
cancel-in-progress: true
jobs:
