Bump docker/setup-buildx-action from 3.8.0 to 3.9.0

Bumps [docker/setup-buildx-action](https://github.com/docker/setup-buildx-action) from 3.8.0 to 3.9.0.
- [Release notes](https://github.com/docker/setup-buildx-action/releases)
- [Commits](docker/setup-buildx-action@v3.8.0...v3.9.0)

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

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

Author: dependabot[bot]

.github/workflows/build-image.yml

@@ -55,7 +55,7 @@ jobs:
         uses: docker/setup-qemu-action@v3
       -
         name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3.8.0
+        uses: docker/setup-buildx-action@v3.9.0
       -
         name: Install Cosign
         uses: sigstore/cosign-installer@v3.8.0

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

@@ -63,7 +63,7 @@ jobs:
         uses: docker/setup-qemu-action@v3
       -
         name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3.8.0
+        uses: docker/setup-buildx-action@v3.9.0
       -
         name: Login to GitHub Container Registry
         uses: docker/login-action@v3.3.0