require('graphql-directive-auth') does not work as intended

Hello!

I have installed the dependency via `npm install graphql-directive-auth` and in order to use it I must first retrieve the `default` property from `require('graphql-directive-auth')` like so:

```js
const AuthDirective = require('graphql-directive-auth').default;
```

Which is not how it is specified in the documentation. This does not happen when using the `import` keyword:

```js
import AuthDirectives from 'graphql-directive-auth';
```

I believe this has something to do with TypeScripts module bundling.

Reproduce the documented require() and import forms after installing graphql-directive-auth, then inspect the package's published TypeScript module output and bundling configuration. Done means the CommonJS usage matches the documentation, or the documentation accurately explains the required default export.

Written by the indexing model from the issue text.