check_pr_label.yml

name: 🏷️ Check labels
on:
  pull_request:
    types: [opened, labeled, unlabeled, synchronize, reopened]
jobs:
    check_labels:
        name: 🏷️ Check valid labels
        runs-on: ubuntu-latest
        steps:
            - name: Check valid labels
              run: |
                  labels=$(jq -r '.pull_request.labels[] | .name' ${{github.event_path }}  | grep 'pr:') 
                  if [[ ! $labels ]]; then
                    echo "::error::You need to provide one or more labels that starts with 'pr:'"
                    exit 1
                  fi
                  exit 0