Incorrect encoding of base64

[ftruter]

WebAuthN spec refers to base64url encoding, not base64

AFAIK Vapor does not have methods to en/decode base64url yet, [but vapor/core does](Please see https://github.com/vapor/core/blob/main/Sources/Core/Data%2BBase64URL.swift)

What would it take to get support for base64url into Vapor/Vapor or into this project?

[ftruter]

Without the proper en/decoding of client tokens this project generates 500 internal server errors now in all browsers that support WebAuthN

[0xTim]

Yeah there's likely places I've misread the spec, I've noticed a few scenarios where it doesn't work and I get a 500 error.

In terms of where base64 URL encoding/decoding should live that will be in this package since the end result will be a library that's framework agnostic, so happy to accept a PR. (May or may not be related to #1)

[0xTim]

Closed via #1