do-not-merge.yml

name: Can be merged
on:
  pull_request:
    types: [opened, labeled, unlabeled, synchronize]
jobs:
  label:
    runs-on: ubuntu-latest
    steps:
      - uses: mheap/github-action-required-labels@v1
        with:
          mode: exactly
          count: 0
          labels: 'Do not merge'