fix: fix TS typings as they are now exported as named exports (#47)

* Update index.d.ts

* Update index.d.ts

Author: wuweiweiwu

index.d.ts

@@ -20,7 +20,7 @@ export type ErrorBoundaryProps =
   | ErrorBoundaryPropsWithComponent
   | ErrorBoundaryPropsWithRender
 
-export default class ErrorBoundary extends React.Component<
+export class ErrorBoundary extends React.Component<
   ErrorBoundaryProps
 > {}