allow for omniauth 2.0 series

[koshilife]

Hi, @camelmasa

OmniAuth 2.0 was released includes to resolved a CSRF vulnerability and some behaviors changed.

See below the release note for details.
https://github.com/omniauth/omniauth/releases/tag/v2.0.0

This PR allow for OmniAuth 2.0 series.

I tested manually in remote server with https communication environment, and confirmed following.

• should use omniauth 2.0 series.
• should return credentials in auth hash. (regression scenarios)

If you want to try my branch, you can use like following in your Gemfile.

gem 'omniauth-thebase', github: 'koshilife/omniauth-thebase', branch: 'allow-for-omniauth-2.0'

[koshilife]

Hi, @camelmasa

For your information I summarized and translated in Japanese the guide of Upgrading to OmniAuth 2.0.

https://zenn.dev/koshilife/articles/b71f8cfcb50e33

I hope it helps you to understand this PR.

[camelmasa]

@koshilife Thanks for creating PR! Recently, I don’t have time😢 I'll review it when I have time 🙏

[koshilife]

thanks for reply!
it's ok and no prolbrem😁