Add action that fails if a PR has no label attached

Author: jacob720

.github/workflows/_label.yml

@@ -0,0 +1,19 @@
+on:
+  workflow_call:
+    inputs:
+        pr_number:
+          required: true
+          type: number
+
+jobs:
+  label:
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+      pull-requests: write
+    steps:
+      - uses: mheap/github-action-required-labels@v5
+        with:
+          count: 1
+        add_comment: true
+        message: "Please attach a label to this PR. This helps with generating helpful release notes."

.github/workflows/ci.yml

@@ -8,6 +8,12 @@ jobs:
   check:
     uses: ./.github/workflows/_check.yml
 
+  require-label:
+    if: github.event_name == 'pull_request'
+    uses: ./.github/workflows/_label.yml
+    with:
+      pr_number: ${{ github.event.pull_request.number }}
+
   lint:
     needs: check
     if: needs.check.outputs.branch-pr == ''