chore(package): update standard to version 7.1.0

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -31,7 +31,7 @@
     "babel": "^5.8.23",
     "chokidar": "^1.2.0",
     "mocha": "^2.3.3",
-    "standard": "^5.3.1"
+    "standard": "^7.1.0"
   },
   "dependencies": {
     "icss-replace-symbols": "^1.0.2",