Update webpack.config and add new devtools setting to speed up builds.

Author: andygup

extra-webpack.config.js

@@ -1,12 +1,15 @@
 const ArcGISPlugin = require('@arcgis/webpack-plugin');
 /**
  * Configuration items defined here will be appended to the end of the existing webpack config defined by the Angular CLI.
+ * 
+ * Note: devtool setting is set for fastest build time: https://webpack.js.org/configuration/devtool/
 */
 module.exports = {
-    plugins: [new ArcGISPlugin()],
-    node: {
-      process: false,
-      global: false,
-      fs: "empty"
-    }
-  }
+  plugins: [new ArcGISPlugin()],
+  node: {
+    process: false,
+    global: false,
+    fs: "empty"
+  },
+  devtool: 'eval'
+}