Update docker/metadata-action action to v6

Author: renovate[bot]

.github/workflows/publish.yaml

@@ -25,7 +25,7 @@ jobs:
 
       - name: Generate Metadata
         id: meta
-        uses: docker/metadata-action@v5
+        uses: docker/metadata-action@v6
         with:
           images: ghcr.io/${{ github.repository }}
           tags: |