change trigger to only on published release

Author: aaearon

.github/workflows/blank.yml

@@ -5,10 +5,8 @@ name: CI
 # Controls when the workflow will run
 on:
   # Triggers the workflow on push or pull request events but only for the "main" branch
-  push:
-    branches: [ "main" ]
-  pull_request:
-    branches: [ "main" ]
+  release:
+    types: [published]
 
   # Allows you to run this workflow manually from the Actions tab
   workflow_dispatch: