ci: run actions only if a new release is created

Author: tldev-de

.github/workflows/build.yml

@@ -1,12 +1,6 @@
 name: Build and Push Docker Image
 
 on:
-  push:
-    branches:
-      - main
-  pull_request:
-    branches:
-      - main
   release:
     types: [created]