chore(package): update prettier to version 2.0.2

Closes #63

Author: greenkeeper[bot]

package.json

@@ -42,7 +42,7 @@
         "del": "^5.1.0",
         "husky": "^3.0.9",
         "mocha": "^6.2.2",
-        "prettier": "^1.18.2",
+        "prettier": "^2.0.2",
         "pretty-quick": "^2.0.0",
         "sinon": "^7.5.0",
         "sinon-chai": "^3.3.0",