chore(package): update prettier to version 1.18.1

Closes #39

Author: greenkeeper[bot]

package.json

@@ -113,7 +113,7 @@
     "jest-watch-typeahead": "0.3.0",
     "json5": "2.1.0",
     "lint-staged": "8.1.5",
-    "prettier": "1.17.0",
+    "prettier": "1.18.1",
     "rollup": "1.10.1",
     "rollup-plugin-commonjs": "9.3.4",
     "rollup-plugin-json": "4.0.0",