Bump docker/metadata-action from 3 to 5 (#11)

Bumps [docker/metadata-action](https://github.com/docker/metadata-action) from 3 to 5.
- [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@v3...v5)

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

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

.github/workflows/docker-master.yaml

@@ -21,7 +21,7 @@ jobs:
 
       - name: Docker meta
         id: meta
-        uses: docker/metadata-action@v3
+        uses: docker/metadata-action@v5
         with:
           images: |
             lablabs/cloudflare_exporter

.github/workflows/docker-release.yaml

@@ -22,7 +22,7 @@ jobs:
 
       - name: Docker meta
         id: meta
-        uses: docker/metadata-action@v3
+        uses: docker/metadata-action@v5
         with:
           images: |
             lablabs/cloudflare_exporter