= New Features

* The internal_request feature now supports WebAuthn, using 
  the following methods:

  * With the webauthn feature:
    * webauthn_setup_params
    * webauthn_setup
    * webauthn_auth_params
    * webauthn_auth
    * webauthn_remove

  * With the webauthn_login feature:
    * webauthn_login_params
    * webauthn_login

* A webauthn_login_user_verification_additional_factor? configuration
  method has been added to the webauthn_login feature. By default,
  this method returns false.  If you configure the method to return
  true, and the WebAuthn credential provided specifies that it
  verified the user, then this will treat the user verification as
  a second factor, so the user will be considered multifactor
  authenticated after successful login.  You should only set this
  method to true if you consider the WebAuthn user verification
  strong enough to be a independent factor.

* A json_response_error? configuration method has been added to the
  json feature.  This should return whether the current response
  should be treated as an error by the json feature.  By default,
  it is true if json_response_error_key is set in the response,
  since that is the default place that Rodauth stores errors when
  using the json feature.

* A webauthn_invalid_webauthn_id_message configuration method has
  been added for customizing the error message used for invalid
  WebAuthn IDs.

= Other Improvements

* The argon2 feature now supports setting the Argon2 p_cost if
  argon2 2.1+ is installed.

* An :invalid_webauthn_id error reason is now used for invalid
  WebAuthn IDs.

* The clear_session method now works as expected for internal
  requests.