Upgrade jsonpointer to address security vulnerability

Author: Axel Niklasson

package.json

@@ -16,7 +16,7 @@
     "generate-function": "^2.0.0",
     "generate-object-property": "^1.1.0",
     "is-my-ip-valid": "^1.0.0",
-    "jsonpointer": "^4.0.0",
+    "jsonpointer": "^5.0.0",
     "xtend": "^4.0.0"
   },
   "devDependencies": {