Add a GitHub Action workflow that fails when PRs are labeled with 'DO…

.github/workflows/do-not-merge-label-check.yml

@@ -0,0 +1,30 @@
+# This GitHub Action workflow is triggered on label changes for pull requests.
+# When a pull request is labeled with "DO NOT MERGE", the workflow fails, thus
+# preventing the pull request from being merged. Otherwise, the workflow will
+# succeed, allowing the pull request to be merged.
+
+name: "Check labels that prevent merge"
+on:
+  pull_request:
+    branches: [main]
+    types: [labeled, unlabeled]
+
+jobs:
+  labels-preventing-merge-check:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        label:
+        # Labels that prevent merging
+        - 'DO NOT MERGE'
+    steps:
+      - name: 'Check "${{ matrix.label }}" label'
+        run: |
+          echo "::notice::Merging permission is diabled for PRs when the '${{ matrix.label }}' label is applied."
+
+          if [ "${{ contains(github.event.pull_request.labels.*.name, matrix.label) }}" = "true" ]; then
+            echo "::error::Pull request is labeled as '${{ matrix.label }}'. Please remove the label before merging."
+            exit 1
+          else
+            exit 0
+          fi