chore(package): update standard to version 13.1.0

Closes #13

Author: greenkeeper[bot]

package.json

@@ -33,7 +33,7 @@
     "mocha": "^6.1.4",
     "nodemon": "^1.19.1",
     "pre-commit": "^1.2.2",
-    "standard": "^12.0.1"
+    "standard": "^13.1.0"
   },
   "standard": {
     "globals": [