Update docker/metadata-action action to v6 (#1056)

| datasource  | package                | from | to |
| ----------- | ---------------------- | ---- | -- |
| github-tags | docker/metadata-action | v5   | v6 |

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

Author: renovate[bot]

.github/workflows/docker-openresty.yml

@@ -49,7 +49,7 @@ jobs:
 
       - name: Docker meta
         id: meta
-        uses: docker/metadata-action@v5
+        uses: docker/metadata-action@v6
         with:
           images: |
             name=opentracing/openresty,enable=${{ github.event_name != 'pull_request' }}

.github/workflows/docker.yml

@@ -64,7 +64,7 @@ jobs:
 
       - name: Docker meta
         id: meta
-        uses: docker/metadata-action@v5
+        uses: docker/metadata-action@v6
         with:
           images: |
             name=opentracing/nginx-opentracing,enable=${{ github.event_name != 'pull_request' }}

.github/workflows/update-docker-images.yml

@@ -118,7 +118,7 @@ jobs:
 
       - name: Docker meta
         id: meta
-        uses: docker/metadata-action@v5
+        uses: docker/metadata-action@v6
         with:
           context: git
           images: |