chore(deps): update actions/checkout action to v6 (#5)

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

Author: renovate[bot]

.github/workflows/docker.yml

@@ -29,7 +29,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Build time variables
         run: |-
           echo "TIMESTAMP=$(git log -1 --pretty=%ct)" >>"$GITHUB_ENV"
@@ -108,7 +108,7 @@ jobs:
       attestations: write
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Build time variables
         run: |-
           echo "TIMESTAMP=$(git log -1 --pretty=%ct)" >>"$GITHUB_ENV"