chore(package): update eslint-config-prettier to version 4.0.0

Closes #111

Author: greenkeeper[bot]

package.json

@@ -24,7 +24,7 @@
   "devDependencies": {
     "ava": "^0.24.0",
     "coveralls": "^3.0.0",
-    "eslint-config-prettier": "^2.2.0",
+    "eslint-config-prettier": "^4.0.0",
     "nunjucks": "^3.0.1",
     "nyc": "^11.0.3",
     "xo": "^0.18.2"