Bump docker/metadata-action from 4 to 5 (#3353)

Bumps [docker/metadata-action](https://github.com/docker/metadata-action) from 4 to 5.
- [Release notes](https://github.com/docker/metadata-action/releases)
- [Upgrade guide](https://github.com/docker/metadata-action/blob/master/UPGRADE.md)
- [Commits](https://github.com/docker/metadata-action/compare/v4...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/build-private-images.yml

@@ -16,7 +16,7 @@ jobs:
     steps:
       - name: Docker meta
         id: meta
-        uses: docker/metadata-action@v4
+        uses: docker/metadata-action@v5
         with:
           images: plausible/analytics-private
           tags: |

.github/workflows/build-public-images.yml

@@ -11,7 +11,7 @@ jobs:
     steps:
       - name: Docker meta
         id: meta
-        uses: docker/metadata-action@v4
+        uses: docker/metadata-action@v5
         with:
           images: plausible/analytics
           tags: |