ci: skip pre-commit workflow on main (#1513)

* ci: skip pre-commit workflow on main

* ci: run pre-commit only on pull requests

Author: thinkall

.github/workflows/pre-commit.yml

@@ -1,9 +1,7 @@
 name: Code formatting
 
 # see: https://help.github.com/en/actions/reference/events-that-trigger-workflows
-on:  # Trigger the workflow on push or pull request, but only for the main branch
-  push:
-    branches: [main]
+on:
   pull_request: {}
 
 defaults: