New update_fastlane command, fastlane_require to auto-install gems & more

* Implement `fastlane_require` to automatically install gems into bundle (#6858)
* Add new `fastlane update_fastlane` action (#6896)
* Support keychains in custom paths and fix non-existing default keychain crash 🔐 (#6887)
* Hide options with no description in docs (#6919)
* Fix commit_version_bump could not find a .xcodeproj (#6676)

https://github.com/fastlane/fastlane/releases/tag/1.108.0
