Use checkout v4

Author: melroy89

starter-workflow-psalm-security-scan.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Psalm Security Scan
         uses: docker://ghcr.io/mbinorg/psalm-security-scan