Bump docker/metadata-action from 5 to 6 (#53)

Author: dependabot[bot]

.github/workflows/docker.yml

@@ -35,7 +35,7 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
       - id: meta
-        uses: docker/metadata-action@v5
+        uses: docker/metadata-action@v6
         with:
           images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
           tags: |