ci: Avoid needlessly running coverage builds (#2815)

Author: olix0r

.github/workflows/coverage.yml

@@ -39,7 +39,7 @@ jobs:
 
   codecov:
     needs: meta
-    if: github.event_name == 'push' || needs.meta.outputs.any_changed == 'true'
+    if: (github.event_name == 'push' && github.ref == 'refs/heads/main') || needs.meta.outputs.any_changed == 'true'
     runs-on: ubuntu-latest
     timeout-minutes: 30
     container: