fix(package): update restify to version 5.2.0

Closes #104

Author: greenkeeper[bot]

package.json

@@ -30,7 +30,7 @@
   },
   "dependencies": {
     "request": "2.81.0",
-    "restify": "4.3.0",
+    "restify": "5.2.0",
     "restify-router": "0.2.1",
     "toobusy-js": "^0.5.1"
   }