ci: Let required runs be triggered by merge group events (#6563)

Co-authored-by: Bart <11445373+bthomee@users.noreply.github.com>

.github/workflows/pre-commit.yml

@@ -1,6 +1,9 @@
 name: Run pre-commit hooks
 
 on:
+  merge_group:
+    types:
+      - checks_requested
   pull_request:
   push:
     branches: