fix: package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/npm:moment:20170905

Latest report for appirio-tech/topcoder-app:
https://snyk.io/test/github/appirio-tech/topcoder-app

Author: snyk-bot

package.json

@@ -66,7 +66,7 @@
     "intro.js": "1.1.1",
     "jstimezonedetect": "1.0.6",
     "lodash": "4.17.4",
-    "moment": "2.18.1",
+    "moment": "2.19.3",
     "moment-timezone": "0.5.13",
     "ng-dialog": "0.5.9",
     "react-select": "1.0.0-beta8",