GitHub Actions concurrency: cancel-in-progress for older runs

mkdir -p .github/workflows
cat > .github/workflows/ci.yml <<'EOF'
name: CI
on:
  push:
    branches: [main]
  pull_request:

concurrency:
  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
  cancel-in-progress: ${{ github.event_name == 'pull_request' }}

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v5
      - run: echo "testing ${{ github.sha }}"
EOF
actionlint -no-color .github/workflows/ci.yml && echo "actionlint: no problems"

jobs:
  deploy:
    runs-on: ubuntu-latest
    concurrency:
      group: deploy-production
      cancel-in-progress: false   # never cancel a deployment halfway