Bump prettier from 1.11.1 to 1.12.0

Bumps [prettier](https://github.com/prettier/prettier) from 1.11.1 to 1.12.0.
- [Release notes](https://github.com/prettier/prettier/releases)
- [Changelog](https://github.com/prettier/prettier/blob/master/CHANGELOG.md)
- [Commits](prettier/prettier@1.11.1...1.12.0)

Signed-off-by: dependabot[bot] <support@dependabot.com>

yarn.lock

@@ -3660,8 +3660,8 @@ preserve@^0.2.0:
   resolved "https://registry.yarnpkg.com/preserve/-/preserve-0.2.0.tgz#815ed1f6ebc65926f865b310c0713bcb3315ce4b"
 
 prettier@^1.11.0:
-  version "1.11.1"
-  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.11.1.tgz#61e43fc4cd44e68f2b0dfc2c38cd4bb0fccdcc75"
+  version "1.12.0"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.12.0.tgz#d26fc5894b9230de97629b39cae225b503724ce8"
 
 pretty-format@^22.4.3:
   version "22.4.3"