Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/verify.yml

@@ -9,7 +9,7 @@ jobs:
     if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name != github.repository
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: run IOC checks
         run: |