Lint only on pull request events (#619)

Author: 0x2b3bfa0

.github/workflows/test.yml

@@ -13,6 +13,7 @@ on:
   - cron: '0 9 * * 1'  # M H d m w (Mondays at 9:00)
 jobs:
   lint:
+    if: github.event_name == 'pull_request'
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2