chore(deps): update actions/checkout action to v6 (#19)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/docker-image.yml

@@ -13,6 +13,6 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v6
     - name: Build the Docker image
       run: docker build . --file Dockerfile --tag t1il/devcord-devmarkt:$(date +%s)

.github/workflows/docker.yml

@@ -21,7 +21,7 @@ jobs:
           running-workflow-name: 'PHP Verify'
           repo-token: ${{ secrets.GITHUB_TOKEN }}
           allowed-conclusions: success
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
       - name: Build Image
         run: docker build . -t ghcr.io/${{ github.repository }}:${{ github.sha }}
       - name: Login to Registry