Update docker/metadata-action action to v6 (#31)

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

Author: renovate[bot]

.github/workflows/ci.yml

@@ -41,7 +41,7 @@ jobs:
 
       - name: Extract metadata for publishing image
         id: meta
-        uses: docker/metadata-action@v5
+        uses: docker/metadata-action@v6
         with:
           images: ${{ env.GHCR_IMAGE }}
 
@@ -109,7 +109,7 @@ jobs:
 
       - name: Create tags for publishing image
         id: meta
-        uses: docker/metadata-action@v5
+        uses: docker/metadata-action@v6
         with:
           images: ${{ env.GHCR_IMAGE }}
           tags: |