Add Workflow to update the stable branch ref to the latest tag (#303)

* Add Workflow to set stable branch ref

* Use workflow from .github repo

---------

Co-authored-by: Karl Higley <karlb@nvidia.com>

.github/workflows/stable-branch.yaml

@@ -0,0 +1,10 @@
+name: Set Stable Branch
+
+on:
+  workflow_dispatch:
+  release:
+    types: [published, deleted]
+
+jobs:
+  set-stable-branch:
+    uses: nvidia-merlin/.github/.github/workflows/set-stable-branch.yaml@main