add on publish trigger

may solve #461

Author: sstidl

.github/workflows/docker-publish.yml

@@ -14,6 +14,8 @@ on:
     tags: ["v*.*.*"]
   pull_request:
     branches: ["{{is_default_branch}}"]
+  release:
+    types: [published]
 
 env:
   # Use docker.io for Docker Hub if empty