build(deps): bump docker/build-push-action from 2.7.0 to 2.8.0

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 2.7.0 to 2.8.0.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v2.7.0...v2.8.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/container-image.yml

@@ -17,7 +17,7 @@ jobs:
     # > will be done directly by buildkit. [...]
     # > any file mutation in the steps that precede [...] will be ignored
     # https://github.com/marketplace/actions/build-and-push-docker-images
-    - uses: docker/build-push-action@v2.7.0
+    - uses: docker/build-push-action@v2.8.0
       with:
         platforms: |
           linux/amd64