build(deps): bump docker/metadata-action from 5.0.0 to 5.5.1 (#7)

Bumps [docker/metadata-action](https://github.com/docker/metadata-action) from 5.0.0 to 5.5.1.
- [Release notes](https://github.com/docker/metadata-action/releases)
- [Commits](96383f4557...8e5442c4ef)

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

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/action.yml

@@ -59,7 +59,7 @@ jobs:
       # https://github.com/docker/metadata-action
       - name: Extract Docker metadata
         id: meta
-        uses: docker/metadata-action@96383f45573cb7f253c731d3b3ab81c87ef81934 # v5.0.0
+        uses: docker/metadata-action@8e5442c4ef9f78752691e2d8f8d19755c6f78e81 # v5.5.1
         with:
           images: |
             evanbuss/opds-proxy