Toggle-able Button in ButtonGroup

[Rc85]

🚀 Feature Proposal

Allow Button props to override ButtonGroup props or implement selectedIndex and onSelect/onPress into ButtonGroup and the button of the selected index will automatically become filled.

Motivation

This would enable a toggle-able ButtonGroup component.

https://material-ui.com/components/toggle-button/

Example

<ButtonGroup appearance='outline'>
  <Button appearance={selectedIndex === 0 ? 'filled' : 'outlined'}>Selected</Button>
  <Button appearance={selectedIndex === 1 ? 'filled' : 'outlined'}>Not Selected</Button>
</ButtonGroup>

[nabeelvalley]

I also think this would be a great addition, so any props on the inner Button's shouldn't be overwritten by the the props on the ButtonGroup