fix(swc): fix typings to match actual exports (#1985)

Fix typings to match actual exports. Allows `import { swc } from ...`

Co-authored-by: Andrew Powell <shellscape@users.noreply.github.com>

Author: gwynne

packages/swc/types/index.d.ts

@@ -8,4 +8,5 @@ import type { Options } from '../src';
  * @param options - Plugin options.
  * @returns Plugin instance.
  */
-export default function swc(options?: Options): Plugin;
+export function swc(options?: Options): Plugin;
+export default swc;