Type doesn't match built output

In the built dist we have 
```
module.exports = WebpackBarPlugin;
```
in `webpackbar.js`, which means it should be imported as
```
import * as WebpackBar from 'webpackbar';
```

However, in generated type, it is declared as
```
export default WebpackBarPlugin;
```
which assumes it is imported as
```
import Webpackbar from 'webpackbar'
```