chore(package): update prettier to version 2.0.5

Closes #47

Author: greenkeeper[bot]

package.json

@@ -33,7 +33,7 @@
   },
   "devDependencies": {
     "eslint": "^6.7.2",
-    "prettier": "^1.19.1",
+    "prettier": "^2.0.5",
     "snazzy": "^8.0.0",
     "standard": "^14.3.1"
   }