chore(package): update standard to version 13.1.0

Closes #271

Author: greenkeeper[bot]

package.json

@@ -64,7 +64,7 @@
     "mocha": "^4.0.1",
     "rsvp": "4.7.0",
     "semantic-release": "^12.2.2",
-    "standard": "^10.0.3",
+    "standard": "^13.1.0",
     "supertest": "^3.0.0",
     "travis-deploy-once": "^4.3.1"
   },