do-not-merge-label.yml

name: Check do-not-merge labels
on:
  pull_request:
    types:
      - opened
      - reopened
      - labeled
      - unlabeled
      - synchronize

jobs:
  test:
    runs-on: ubuntu-latest
    name: Check do-not-merge labels
    steps:
      - name: Get PR labels
        id: pr-labels
        uses: joerick/pr-labels-action@v1.0.9

      - run: |
          echo "A 'do-not-merge/*' label has been found in this PR."
          exit 1
        if: contains(steps.pr-labels.outputs.labels, 'do-not-merge')