fix(package): update ajv to version 6.5.0

Closes #8

Author: greenkeeper[bot]

package.json

@@ -10,7 +10,7 @@
     "eslint"
   ],
   "dependencies": {
-    "ajv": "^5.2.2",
+    "ajv": "^6.5.0",
     "eslint": "^3.19.0",
     "eslint-config-airbnb-base": "^11.2.0",
     "eslint-config-standard": "^10.2.1",