[d16-8] Add label checks. (#9969)

.github/workflows/label-checker.yml

@@ -0,0 +1,22 @@
+name: Labels verification
+on:
+  pull_request:
+    types: [opened, reopened, labeled, unlabeled, synchronize]
+
+jobs:
+  labels-check:
+    runs-on: ubuntu-latest
+    name: Labels verification
+
+    steps:
+    - run: exit 0
+      # always happy if monojenkins
+      if: github.actor == 'monojenkins'
+
+    - run: exit 1
+      # failure if not monojenkins and no labels
+      if: github.actor != 'monojenkins' && join(github.event.pull_request.labels, ',') == ''
+
+    - run: exit 0
+      # success if not monojenkins but labels
+      if: github.actor != 'monojenkins' && join(github.event.pull_request.labels, ',') != ''