Update dependency webpack to v4.40.2

Author: renovate-bot

package.json

@@ -104,7 +104,7 @@
     "script-ext-html-webpack-plugin": "2.1.4",
     "style-loader": "0.23.1",
     "terser-webpack-plugin": "1.4.1",
-    "webpack": "4.39.1",
+    "webpack": "4.40.2",
     "webpack-cli": "3.3.6",
     "webpack-dev-server": "3.7.2",
     "webpack-merge": "4.2.1"