Support TypeScript 3.8

[levrik]

Can't use the new type imports introduced by TypeScript 3.8

SyntaxError: /Users/levrik/code/<redacted>/src/theme.ts: Unexpected token (3:12)

  1 | import { createMuiTheme, emphasize } from '@material-ui/core/styles';
  2 | import createPalette from '@material-ui/core/styles/createPalette';
> 3 | import type { SkeletonClassKey } from '@material-ui/lab/Skeleton';

https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-8.html#type-only-imports-exports

react-script 3.4.0
TypeScript 3.8.0

[MichaelDeBoey]

Closed by #8681

[ianschmitz]

This should be available in react-scripst@3.4.1.