Error on sending number as string

Hey guys,

The APIs `createOrg` and `createMagicLink` returns an error from PropelAuth servers when the parameters `maxUsers` and `expiresInHours`, respectivelly, are sent as string.

Also, the parameter [expiresInHours](https://github.com/PropelAuth/node/blob/3a4e1ea265341cda9c152f6b7a110a95409af9a4/src/api/magicLink.ts#L9) in `createMagicLink` function is incorrectly typed.
