v5.0.3
Jest [doesn't support package exports](https://github.com/facebook/jest/issues/9771), nor does it support `browser` overrides out of the box (though it [can be configured](https://jestjs.io/docs/configuration#resolver-string)). This means it parses the stubbed files introduced in #13 as javascript, so let's just require and export the file that the stub is stubbing. This has the added bonus of also supporting old nodes that don't understand package exports. Fixes achingbrain/uint8arrays#21