deps: update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/test.yml

@@ -31,7 +31,7 @@ jobs:
         uses: docker/setup-buildx-action@v3
 
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - uses: azure/setup-kubectl@v3.2
         with: