chore(package): update eslint-config-prettier to version 6.7.0

Closes #13

Author: greenkeeper[bot]

package.json

@@ -30,7 +30,7 @@
     "assert-dotenv": "^3.0.0",
     "coveralls": "^3.0.2",
     "eslint": "^5.4.0",
-    "eslint-config-prettier": "^3.0.1",
+    "eslint-config-prettier": "^6.7.0",
     "eslint-config-xo": "^0.24.2",
     "eslint-plugin-json": "^1.2.1",
     "eslint-plugin-prettier": "^2.6.2",