Merge pull request #168 from redbastie/patch-3

[3.x] Add sourcemaps to webpack config

Author: taylorotwell

Diff for: src/Presets/bootstrap-stubs/webpack.mix.js

@@ -12,4 +12,5 @@ const mix = require('laravel-mix');
  */
 
 mix.js('resources/js/app.js', 'public/js')
-    .sass('resources/sass/app.scss', 'public/css');
+    .sass('resources/sass/app.scss', 'public/css')
+    .sourceMaps();