Update actions/checkout action to v3

Author: renovate-bot

.github/workflows/policy.yaml

@@ -9,6 +9,6 @@ jobs:
   policy:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@7884fcad6b5d53d10323aee724dc68d8b9096a2e # tag=v2.4.2
+      - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b # tag=v3.0.2
       - uses: docker://ghcr.io/policy-as-versioned-code/policy-checker:latest