Update docker/metadata-action action to v6

Author: renovate[bot]

.github/workflows/publish_docker.yml

@@ -27,7 +27,7 @@ jobs:
 
       - name: Extract metadata for Docker
         id: meta
-        uses: docker/metadata-action@v2
+        uses: docker/metadata-action@v6
         with:
           images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
           tags: |