Bump docker/setup-buildx-action from 1.5.1 to 1.6.0

Bumps [docker/setup-buildx-action](https://github.com/docker/setup-buildx-action) from 1.5.1 to 1.6.0.
- [Release notes](https://github.com/docker/setup-buildx-action/releases)
- [Commits](https://github.com/docker/setup-buildx-action/compare/v1.5.1...v1.6.0)

---
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>

.github/workflows/docker-build.yml

@@ -11,7 +11,7 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v2
     - name: Setup Docker Buildx
-      uses: docker/setup-buildx-action@v1.5.1
+      uses: docker/setup-buildx-action@v1.6.0
       id: buildx
       with:
         install: true