Bump docker/metadata-action from 5.5.1 to 5.6.1 in /.github/workflows

Bumps [docker/metadata-action](https://github.com/docker/metadata-action) from 5.5.1 to 5.6.1.
- [Release notes](https://github.com/docker/metadata-action/releases)
- [Commits](docker/metadata-action@8e5442c...369eb59)

---
updated-dependencies:
- dependency-name: docker/metadata-action
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/docker.yml

@@ -28,7 +28,7 @@ jobs:
 
       - name: Extract metadata (tags, labels) for Docker
         id: meta
-        uses: docker/metadata-action@8e5442c4ef9f78752691e2d8f8d19755c6f78e81
+        uses: docker/metadata-action@369eb591f429131d6889c46b94e711f089e6ca96
         with:
           images: ghcr.io/clasp-developers/clasp
           tags: |