Add base64 as an inlined implementation

[olleolleolle]

This avoids a warning emitted by Ruby 3.3.0-preview2.

Fixes #401.

EDIT: inline the base64 implementation, and leave code comments that remind the reader about what they are seeing there.

Turn the base64 gem into a spec-supporting development dependency.

[santiagorodriguez96]

Hey @olleolleolle! Thank you so much for your contribution!

However, we were thinking about just inlining the implementation of base64 since it's just a thin wrapper and we don't even need all its methods.

Feel free making this adjustment in this PR (or create a new one). Otherwise I will try creating a new PR for the inlining change in the coming week 🙂

[olleolleolle]

@santiagorodriguez96 Hope your weekend's good!

[santiagorodriguez96]

Thank you so much! ❤️

Have a nice weekend you too!

[Earlopain]

I think there's something missing here. The require in the file is still present, and U2fMigrator still calls base64 methods.

[olleolleolle]

@Earlopain

webauthn-ruby/lib/webauthn/u2f_migrator.rb

Line 46 in 657a278

@attestation_trust_path ||= [OpenSSL::X509::Certificate.new(Base64.strict_decode64(@certificate))]

Indeed! In order to capture that where it can be seen, Issue #422.