github-action: bump docker/metadata-action from 4.6.0 to 5.0.0

Bumps [docker/metadata-action](https://github.com/docker/metadata-action) from 4.6.0 to 5.0.0.
- [Release notes](https://github.com/docker/metadata-action/releases)
- [Upgrade guide](https://github.com/docker/metadata-action/blob/master/UPGRADE.md)
- [Commits](docker/metadata-action@818d4b7...96383f4)

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

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/build-image-base.yml

@@ -65,7 +65,7 @@ jobs:
 
       - name: Extract metadata (tags, labels) for ghcr
         id: meta-ghcr
-        uses: docker/metadata-action@818d4b7b91585d195f67373fd9cb0332e31a7175
+        uses: docker/metadata-action@96383f45573cb7f253c731d3b3ab81c87ef81934
         with:
           images: ghcr.io/alphagov/paas/${{ inputs.image }}
           tags: |
@@ -80,7 +80,7 @@ jobs:
             org.opencontainers.image.title=GOV.UK PaaS ${{ inputs.image }}
       - name: Extract metadata (tags, labels) for docker hub
         id: meta-dockerhub
-        uses: docker/metadata-action@818d4b7b91585d195f67373fd9cb0332e31a7175
+        uses: docker/metadata-action@96383f45573cb7f253c731d3b3ab81c87ef81934
         with:
           images: governmentpaas/${{ inputs.image }}
           tags: |