fix webpack version as there is an issue with beta version bigger than 22

Author: dweber019

package.json

@@ -130,7 +130,7 @@
     "ts-node": "^1.3.0",
     "typescript": "^2.0.0",
     "wait-on": "^1.5.2",
-    "webpack": ">=2.1.0-beta.18 || ^2.1.0",
+    "webpack": "=2.1.0-beta.22 || ^2.1.0",
     "webpack-dev-server": ">=2.1.0-beta.0 || ^2.1.0",
     "webpack-notifier": "^1.4.1"
   }