chore(package): update eslint to version 3.4.0 (#175)

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -56,7 +56,7 @@
   },
   "devDependencies": {
     "babel-eslint": "6.1.2",
-    "eslint": "3.3.1",
+    "eslint": "3.4.0",
     "eslint-plugin-babel": "3.3.0",
     "eslint-plugin-flowtype": "2.11.4",
     "eslint-plugin-react": "6.1.2",