Update openid_connect to 2.2

[takahashim]

I am trying to use omniauth_openid_connect in a service using the apple_id gem. However, it seems that the version of openid_connect that omniauth_openid_connect depends on is outdated, making it impossible to install with the version of the apple_id gem we are using. So, I would like to make omniauth_openid_connect compatible with the newer version of openid_connect.

• Note that the openid_connect gem changed from HTTPClient to Faraday in version 2.x, so some modifications will be necessary. But the dependency is small (used only in fetch_key method and tests), so I believe the required changes will be minimal.

[davidwessman]

The changes in openid_connect seems to match very well with your changes, looks good to me 🙂

[stanhu]

Dropped Ruby 2.5 and 2.6 CI support in https://github.com/omniauth/omniauth_openid_connect/pull/154.

[takahashim]

Thank you for merging!

[raivil]

@takahashim Found this possible issue with the update. https://github.com/omniauth/omniauth_openid_connect/issues/156 Can you check it out?

[takahashim]

@raivil Thank you for notifying me. I will check it later.