fix/553-require-rp-id-auth-options

[MasterKale]

This PR makes the rpID argument a required one when calling generateAuthenticationOptions().

Fixes #553.

Breaking changes

Before:

  generateRegistrationOptions({ rpID: 'example.com', ... });
generateAuthenticationOptions();

After:

  generateRegistrationOptions({ rpID: 'example.com', ... });
generateAuthenticationOptions({ rpID: 'example.com' });