DNM: run container publish on push

Author: markgoddard

.github/workflows/container-publish.yml

@@ -2,7 +2,7 @@
 name: Publish container repositories
 on:
   push:
-    branches: [main]
+    branches: [main, container-promote-mk3]
     paths:
       - '.github/workflows/container-publish.yml'
       - 'ansible/dev-pulp-container-publish.yml'