Bump docker/metadata-action from 4.5.0 to 4.6.0 (#750)

Bumps [docker/metadata-action](https://github.com/docker/metadata-action) from 4.5.0 to 4.6.0.
- [Release notes](https://github.com/docker/metadata-action/releases)
- [Commits](docker/metadata-action@2c0bd77...818d4b7)

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

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -176,7 +176,7 @@ jobs:
 
       - name: Docker meta
         id: meta
-        uses: docker/metadata-action@2c0bd771b40637d97bf205cbccdd294a32112176 # v4.5.0
+        uses: docker/metadata-action@818d4b7b91585d195f67373fd9cb0332e31a7175 # v4.6.0
         with:
           images: |
             name=ghcr.io/nginxinc/nginx-kubernetes-gateway