chore(package): update standard to version 8.1.0

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -15,7 +15,7 @@
     "coveralls": "2.11.13",
     "nyc": "8.3.0",
     "semantic-release": "^4.3.5",
-    "standard": "8.0.0",
+    "standard": "8.1.0",
     "tape": "4.6.0"
   },
   "repository": {