chore(package): update eslint to version 3.18.0

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -50,7 +50,7 @@
   },
   "devDependencies": {
     "assert-diff": "^1.2.0",
-    "eslint": "3.17.0",
+    "eslint": "3.18.0",
     "eslint-plugin-markdown": "^1.0.0-beta.2",
     "husky": "^0.13.0",
     "portfinder": "^1.0.10",