Bump docker/setup-buildx-action from 3.7.1 to 3.9.0

Bumps [docker/setup-buildx-action](https://github.com/docker/setup-buildx-action) from 3.7.1 to 3.9.0.
- [Release notes](https://github.com/docker/setup-buildx-action/releases)
- [Commits](docker/setup-buildx-action@c47758b...f7ce87c)

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

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

Author: dependabot[bot]

.github/workflows/ci-variant.yaml

@@ -65,7 +65,7 @@ jobs:
     - name: Set up Docker Buildx
       uses:
         # yamllint disable-line rule:line-length
-        docker/setup-buildx-action@c47758b77c9736f4b2ef4073d4d51994fabfe349  # v3.7.1
+        docker/setup-buildx-action@f7ce87c1d6bead3e36075b2ce75da1f6cc28aaca  # v3.9.0
     - name: Build image
       uses:
         # yamllint disable-line rule:line-length