chore(deps): update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/docker-image.yml

@@ -6,7 +6,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up QEMU
       uses: docker/setup-qemu-action@v3
       with: