chore(prettier): update to @latest

Author: greenkeeper[bot]

package.json

@@ -78,7 +78,7 @@
     "markdown-magic-install-command": "1.3.1",
     "markdown-magic-package-scripts": "1.2.1",
     "nsp": "^3.2.1",
-    "prettier": "1.11.1",
+    "prettier": "1.12.0",
     "semantic-release": "15.1.6",
     "standard-version": "4.3.0"
   },