Update build tools.

Author: ryanelian

package.json

@@ -18,8 +18,8 @@
   "devDependencies": {
     "ts-loader": "^4.3.0",
     "typescript": "^2.8.3",
-    "webpack": "^4.8.1",
-    "webpack-cli": "^2.1.3"
+    "webpack": "^4.8.3",
+    "webpack-cli": "^2.1.4"
   },
   "dependencies": {}
 }