Add controlled mode to select #198

Is your feature request related to a problem? Please describe.
I run to this problem where I want to have a confirm modal popping up after an option is selected.
But after I select the state has changed already and I have no way to control it and change it back if the user choose to cancel it.

Describe the solution you'd like
I want to have a control of the internal state: selectedOptionIndex, selectedOption, or else.
A nice react Select library should have 2 mode: uncontrolled and controlled.
It can be like
<Select value={...} options={[...]}>

Additional context
Some hacky solution: I remount the component by setting the new key and set default option to be the other one.