Update docker

Changes:

- https://github.com/docker-library/docker/commit/86f7f4b: Update to 19.03.12
- https://github.com/docker-library/docker/commit/8fe469c: Merge pull request https://github.com/docker-library/docker/pull/179 from infosiftr/channel-alias

library/docker

@@ -1,25 +1,25 @@
-# this file is generated via https://github.com/docker-library/docker/blob/34acb095295d0cd1e3cb6a4098c9a71069a6362e/generate-stackbrew-library.sh
+# this file is generated via https://github.com/docker-library/docker/blob/606c63960a4845af7077721eb3900c706f5d0c5e/generate-stackbrew-library.sh
 
 Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Joseph Ferguson <[email protected]> (@yosifkit)
 GitRepo: https://github.com/docker-library/docker.git
 
-Tags: 19.03.11, 19.03, 19, stable, test, latest
+Tags: 19.03.12, 19.03, 19, stable, test, latest
 Architectures: amd64, arm32v6, arm32v7, arm64v8
-GitCommit: eb305f71421bf772cfac2a46571280ff90f60033
+GitCommit: 86f7f4b563c7c6fe4620c5a8d82694a78f41989f
 Directory: 19.03
 
-Tags: 19.03.11-dind, 19.03-dind, 19-dind, stable-dind, test-dind, dind
+Tags: 19.03.12-dind, 19.03-dind, 19-dind, stable-dind, test-dind, dind
 Architectures: amd64, arm32v6, arm32v7, arm64v8
 GitCommit: a73d96e731e2dd5d6822c99a9af4dcbfbbedb2be
 Directory: 19.03/dind
 
-Tags: 19.03.11-dind-rootless, 19.03-dind-rootless, 19-dind-rootless, stable-dind-rootless, test-dind-rootless, dind-rootless
+Tags: 19.03.12-dind-rootless, 19.03-dind-rootless, 19-dind-rootless, stable-dind-rootless, test-dind-rootless, dind-rootless
 Architectures: amd64
 GitCommit: 25c81c65fe4e971ff75e67df38e8b9970b523f6e
 Directory: 19.03/dind-rootless
 
-Tags: 19.03.11-git, 19.03-git, 19-git, stable-git, test-git, git
+Tags: 19.03.12-git, 19.03-git, 19-git, stable-git, test-git, git
 Architectures: amd64, arm32v6, arm32v7, arm64v8
 GitCommit: 7a67842e7ff12c1426ae6a67ac1b7a701b51f3df
 Directory: 19.03/git