use biometric based check instead of a PIN as a security measure in VCI

[Kristina Yasuda]

currently we define user_pin_required parameter. but there are use-cases emerging that rely on the biometric based face check to do a security check. probably a good idea to define a parameter for that biometric_check_required or something..?

[Mark Haine]

Migrated to GitHub

https://github.com/openid/OpenID4VCI