chore(package): update prettier to version 1.12.1

Closes #2521

Author: greenkeeper[bot]

package.json

@@ -169,7 +169,7 @@
     "minimist": "1.2.0",
     "mkdirp": "0.5.1",
     "pify": "3.0.0",
-    "prettier": "1.11.1",
+    "prettier": "1.12.1",
     "pretty-bytes": "4.0.2",
     "pretty-quick": "1.4.1",
     "prop-types": "15.6.1",