Update docker/metadata-action action to v6

Author: renovate[bot]

.github/workflows/docker-image.yml

@@ -23,7 +23,7 @@ jobs:
         submodules: recursive
     - name: Docker meta
       id: docker_meta
-      uses: docker/metadata-action@v5
+      uses: docker/metadata-action@v6
       with:
         images: ${{ env.REGISTRY }}/${{ github.repository }}
         tags: |