Merge pull request #5859 from mboersma/update-security-branches

Update active branches for security scanner

Author: k8s-ci-robot

.github/workflows/weekly-security-scan.yaml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        branch: [ main, release-1.20, release-1.19 ]
+        branch: [ main, release-1.21, release-1.20 ]
     name: Trivy
     runs-on: ubuntu-latest
     steps: