chore: Add GitHub Actions workflow for monthly label updates using reusable workflow

Author: snovak7

.github/workflows/cron-update-labels.yml

@@ -0,0 +1,21 @@
+# Utility that updates labels based on keystone reusable workflow repository
+name: "Monthly Label Timer"
+on:
+  # Manually run the job
+  workflow_dispatch:
+  # Periodically run the job
+  # Every first day of the month at 1:27 UTC
+  schedule:
+    - cron: "28 1 1 * *"
+
+# Grant only what’s needed; label management requires issues: write
+permissions:
+  contents: read
+  issues: write
+
+jobs:
+  # Runs reusable workflow (utility-update-labels.yml on the main branch) from keystone repository
+  create-labels:
+    name: "Update Labels"
+    uses: escendit/keystone/.github/workflows/utility-update-labels.yml@main
+    secrets: inherit