cleanupOutputBeforeBuild(cleanOptionsCallback = () => {}) {
        webpackConfig.cleanupOutputBeforeBuild(cleanOptionsCallback);

        return this;
    }
If enabled, the output directory is emptied between each build (to remove old files).

A list of available options can be found at https://webpack.js.org/configuration/output/#outputclean

For example:

```
Encore.cleanupOutputBeforeBuild((options) => {
    options.dry = true;
})
```

@param {OptionsCallback<Exclude<ConstructorParameters<typeof webpack.CleanPlugin>[0], undefined>>} cleanOptionsCallback
@returns {Encore}