Auth Caching

* Cache Apple auth credentials to avoid multiple logins and rate limiting (#11108) via Felix Krause
Fix: can't create instances of Client because of: instance variable @client not initialized (#10439) via Joshua Liebowitz
Add check & error message if gym provided plist can't be found (#10825) via Felix Krause

https://github.com/fastlane/fastlane/releases/tag/2.68.2
