Update workflow to build on pull request only

.github/workflows/Build+push Immich.yml

@@ -6,8 +6,8 @@ on:
     # * is a special character in YAML so you have to quote this string
     #- cron:  '0 0 * * *'
   workflow_dispatch:
-  push:
-    branches: [ main ]
+  #push:
+    #branches: [ main ]
   pull_request:
     branches: [ main ]