Typescript definition: disable allowSyntheticDefaultImports behavior

[rokoroku]

import React from "react"
       ~~~~~
// .../node_modules/@types/react/index"' can only be default-imported using the 'allowSyntheticDefaultImports' flag

Importing react-async from non-allowSyntheticDefaultImports-enabled project, the included typescript definition emits above error message.

Since the default value of the flag is not true, it'd be better turning it off I think.
microsoft/TypeScript#10895

[ghengeveld]

I'm not familiar with this particular setting or situation, so I'm not sure how to resolve this. What do you suggest we do to fix this? Perhaps you can open a PR to fix our setup?

[rokoroku]

Sure, I'll submit a simple PR :)

[rokoroku]

Fixed by #112