addCacheGroup(name, options) {
        webpackConfig.addCacheGroup(name, options);

        return this;
    }
Add a new cache group to Webpack's SplitChunksPlugin.
This can, for instance, be used to extract code that
is common to multiple entries into its own chunk.

See: https://webpack.js.org/plugins/split-chunks-plugin/#examples

For example:

```
Encore.addCacheGroup('vendor', {
    test: /[\\/]node_modules[\\/]react/
});
```

You can pass all the options supported by the SplitChunksPlugin
but also the following shorthand provided by Encore:

- `node_modules`: An array of `node_modules` packages names

For example:

```
Encore.addCacheGroup('vendor', {
    node_modules: ['react', 'react-dom']
});
```

At least one of the `test` or the `node_modules` option
should be provided.

By default, the new cache group will be created with the
following options:
- `chunks` set to `"all"`
- `enforce` set to `true`
- `name` set to the value of the "name" parameter

@param {string} name The chunk name (e.g. vendor to create a vendor.js)
@param {object} options Cache group option
@returns {Encore}