chore(package): update lockfile

https://npm.im/greenkeeper-lockfile

Author: greenkeeperio-bot

yarn.lock

@@ -5026,9 +5026,9 @@ preserve@^0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/preserve/-/preserve-0.2.0.tgz#815ed1f6ebc65926f865b310c0713bcb3315ce4b"
 
-prettier@1.11.1:
-  version "1.11.1"
-  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.11.1.tgz#61e43fc4cd44e68f2b0dfc2c38cd4bb0fccdcc75"
+prettier@1.12.1:
+  version "1.12.1"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.12.1.tgz#c1ad20e803e7749faf905a409d2367e06bbe7325"
 
 [email protected]:
   version "4.0.2"