Publish container upon release

.github/workflows/publish-container.yml

@@ -2,8 +2,8 @@
 name: Create and publish a Docker image
 
 on:
-  push:
-    branches: ['main']
+  release:
+    types: [published]
 
 # Defines two custom environment variables for the workflow. These are used for the Container registry domain, and a name for the Docker image that this workflow builds.
 env: