update version of xml2js to 0.4.23, fixes #479

Author: gugu

package.json

@@ -38,7 +38,7 @@
     "passport-strategy": "*",
     "xml-crypto": "^2.0.0",
     "xml-encryption": "1.2.1",
-    "xml2js": "0.4.x",
+    "xml2js": "^0.4.23",
     "xmlbuilder": "^11.0.0",
     "xmldom": "0.1.x"
   },