Bump docker/setup-buildx-action from 2.5.0 to 2.6.0 (#725)

Bumps [docker/setup-buildx-action](https://github.com/docker/setup-buildx-action) from 2.5.0 to 2.6.0.
- [Release notes](https://github.com/docker/setup-buildx-action/releases)
- [Commits](docker/setup-buildx-action@4b4e9c3...6a58db7)

---
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

@@ -157,7 +157,7 @@ jobs:
           key: nginx-kubernetes-gateway-${{ github.run_id }}-${{ github.run_number }}
 
       - name: Docker Buildx
-        uses: docker/setup-buildx-action@4b4e9c3e2d4531116a6f8ba8e71fc6e2cb6e6c8c # v2.5.0
+        uses: docker/setup-buildx-action@6a58db7e0d21ca03e6c44877909e80e45217eed2 # v2.6.0
 
       - name: Setup QEMU
         uses: docker/setup-qemu-action@e81a89b1732b9c48d79cd809d8d81d79c4647a18 # v2.1.0