Update actions/checkout action to v2.4.2

Author: renovate-bot

.github/workflows/ci.yml

@@ -9,6 +9,6 @@ jobs:
   policy:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@ec3a7ce113134d7a93b817d10a8272cb61118579 # renovate: tag=v2.4.0
+      - uses: actions/checkout@7884fcad6b5d53d10323aee724dc68d8b9096a2e # tag=v2.4.2
       - uses: docker://ghcr.io/example-policy-org/policy-checker:latest