chore(deps): update actions/checkout action to v5

Author: renovate[bot]

.github/workflows/integration-test.yaml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           fetch-depth: 0
       - run: docker build --load -t helmfile-nix .