fix(package): update package-json to version 6.3.0

Closes #1015

Author: greenkeeper[bot]

package.json

@@ -42,7 +42,7 @@
     "csurf": "1.9.0",
     "express": "4.13.4",
     "json-file-plus": "3.2.0",
-    "package-json": "5.0.0",
+    "package-json": "6.3.0",
     "passport": "0.4.0",
     "passport-local": "1.0.0",
     "react-helmet": "5.2.0"