Bump docker/setup-buildx-action from 2.8.0 to 2.9.1 (#909)

Bumps [docker/setup-buildx-action](https://github.com/docker/setup-buildx-action) from 2.8.0 to 2.9.1.
- [Release notes](https://github.com/docker/setup-buildx-action/releases)
- [Commits](docker/setup-buildx-action@v2.8.0...4c0219f)

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -168,7 +168,7 @@ jobs:
           key: nginx-kubernetes-gateway-${{ github.run_id }}-${{ github.run_number }}
 
       - name: Docker Buildx
-        uses: docker/setup-buildx-action@16c0bc4a6e6ada2cfd8afd41d22d95379cf7c32a # v2.8.0
+        uses: docker/setup-buildx-action@4c0219f9ac95b02789c1075625400b2acbff50b1 # v2.9.1
 
       - name: Docker meta
         id: meta