chore(package): update prettier to version 2.0.4

Closes #42

Author: greenkeeper[bot]

package.json

@@ -69,7 +69,7 @@
     "husky": "^2.0.0",
     "jest": "^23.6.0",
     "lint-staged": "^9.0.0",
-    "prettier": "^1.15.3",
+    "prettier": "^2.0.4",
     "react-addons-test-utils": "^15.6.2",
     "regenerator-runtime": "^0.13.1",
     "webpack-cli": "^3.2.1"