enableSourceMaps(enabled = true) {
        webpackConfig.enableSourceMaps(enabled);

        return this;
    }
When enabled, all final CSS and JS files will be rendered
with sourcemaps to help debugging.

The *type* of source map will differ between a development
or production build.

For example if you want to always generate sourcemaps:

```
Encore.enableSourceMaps();
```

Or only enable them when not in production mode:

```
Encore.enableSourceMaps(!Encore.isProduction());
```

@param {boolean} enabled
@returns {Encore}