chore(package): update prettier to version 2.0.3

Closes #14

Author: greenkeeper[bot]

package.json

@@ -30,7 +30,7 @@
     "@types/node": "^10.3.6",
     "husky": "^0.14.3",
     "jest": "^23.2.0",
-    "prettier": "^1.13.6",
+    "prettier": "^2.0.3",
     "source-map": "^0.7.3",
     "ts-jest": "^22.4.6",
     "tsc-watch": "^1.0.22",