build: bump prettier from 1.11.1 to 1.12.1

Bumps [prettier](https://github.com/prettier/prettier) from 1.11.1 to 1.12.1.
- [Release notes](https://github.com/prettier/prettier/releases)
- [Changelog](https://github.com/prettier/prettier/blob/master/CHANGELOG.md)
- [Commits](prettier/prettier@1.11.1...1.12.1)

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

package.json

@@ -31,7 +31,7 @@
     "lerna": "^2.9.1",
     "markdownlint-cli": "^0.8.1",
     "npm-run-all": "^4.1.2",
-    "prettier": "^1.11.1",
+    "prettier": "^1.12.1",
     "replace-in-file": "^3.4.0",
     "ts-config": "^18.0.0",
     "ts-jest": "^22.4.2",

yarn.lock

@@ -3984,9 +3984,9 @@ 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"
 
 pretty-format@^22.4.3:
   version "22.4.3"