chore(package): update prettier to version 1.18.0

Closes #6

Author: greenkeeper[bot]

package.json

@@ -35,7 +35,7 @@
         "@types/node": "^10.12.2",
         "@types/webpack-merge": "~4.1.3",
         "np": "~3.0.4",
-        "prettier": "~1.14.3",
+        "prettier": "~1.18.0",
         "tslint": "~5.11.0",
         "tslint-config-airbnb": "~5.11.0",
         "tslint-config-prettier": "~1.15.0",