Xcode 9 improvements

* Make `rollout` value in supply optional (#9997) via Felix Krause
* Apple pay merchant association (#9887) via Daniel Bowden
* Remove `--login` from xcbuild-safe.sh as per suggestion (#9976) via Felix Krause
* [scan] Improve Xcode version detection (#9999) via Felix Krause
* [gym] Improve Xcode version detection (#10002) via Felix Krause
* Remove unused snapshot code (#10003) via Felix Krause
* Fix call to iTMSTransporter for Xcode 9 (#10004) via David Ohayon
* Do not attempt to retrieve Xcode version on non-Mac platform (#9998) via Sander Lijbrink
* remove factory/unfolding usage (#9990) via Stefan Natchev
* Ignore Apple Watch screenshots (improved) (#9988) via Claes Jacobsson
* Looking for a member by email doesn't work if we only have AppleId (#9982) via Joshua Liebowitz
* [spaceship] Add support for listing invites (aka pending members) (#9938) via Alexander

https://github.com/fastlane/fastlane/releases/tag/2.52.0
