Trigger for push or pull_request only on main.

.github/workflows/tests.yml

@@ -1,6 +1,13 @@
 name: tests
 
-on: [push, pull_request, workflow_dispatch]
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+  workflow_dispatch:
 
 jobs: