Trigger publish workflow on element1-backports. (#4073)

Author: davidmorgan

.github/workflows/publish.yaml

@@ -4,7 +4,7 @@ name: Publish
 
 on:
   pull_request:
-    branches: [ master ]
+    branches: [ master, element1-backports ]
     types: [opened, synchronize, reopened, labeled, unlabeled]
   push:
     tags: [ '[A-z]+-v[0-9]+.[0-9]+.[0-9]+*' ]