Workflow to check that a PR has a milestone set

.github/workflows/check-pr-has-milestone.yml

@@ -0,0 +1,32 @@
+name: "Check PR Has Milestone"
+
+on:
+  pull_request_target:
+    types: [ opened, edited, synchronize, reopened ]
+    branches:
+    - dev
+    - master
+    - V6
+
+concurrency:
+  group: "check-pr-milestone-${{ github.head_ref || github.run_id }}-${{ github.event_name }}"
+  cancel-in-progress: true
+
+jobs:
+  fail-on-bad-milestone:
+    name: Fail if Pull Request has no Associated Version Milestone
+    runs-on: ubuntu-latest
+    steps:
+    - name: Fail if no Milestone Set
+      if: github.event.pull_request.milestone == null
+      run: |
+        echo "::error::Pull request must have milestone set!"
+        exit 1
+
+    - name: Fail if Invalid Milestone Set
+      run: |
+        if [[ ${{ github.event.pull_request.milestone }} =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
+            exit 0
+        fi
+        echo "::error::Pull request has non-standard milestone!"
+        exit 1