Update GH action to publish SN on 0.18.x push

Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>

Author: tzolov

.github/workflows/publish-snapshot.yml

@@ -2,7 +2,7 @@ name: Publish Snapshot
 
 on:
   push:
-    branches: [ "main" ]
+    branches: [ "main", "0.18.x" ]
 
 jobs:
   build: