ci: Update remote docker version (#2487)

* ci: Update remote docker version

The nightly CI fails because default remote docker (17.09.0-ce) does
not support DOCKER_BUILDKIT. Updating the remote docker version to be at
least 18.09 fixes this.

* Kick build, fix whitespace
Co-authored-by: Matthew Slipper <me@matthewslipper.com>

.circleci/config.yml

@@ -277,7 +277,8 @@ jobs:
       - image: circleci/buildpack-deps:stretch
     steps:
       - checkout
-      - setup_remote_docker
+      - setup_remote_docker:
+          version: 20.10.12
       - when:
           condition: <<parameters.target>>
           steps: