Update react-select libdef

[kangax]

• Adds Select.Async
• Makes Props exact so that they're actually type-safe
• Fixes faulty autofocus test (as found by exact Props)
• Defines OptionType in tests the same way as it is defined in react-select
• Adds a test for an invalid prop

[kangax]

@AndrewSouthpaw @villesau @gantoine there are few stylistic changes from the Prettier running in my VSCode. Let me know if I should discard those. On the other hand, it'd be nice to have Prettier running by default in the repo, avoiding any tiny inconsistencies. Was this ever considered?

[gantoine]

As long as it's running this project's config for prettier they're ok to keep.