Support setting XCode Version

[dahlmo]

Description

Suggesting adding a parameter that allows setting the XCode version. This would allow users to both set SDK version (already supported) and set XCode version if required.

Proposal

Support second parameter xcode-version in the runner, which sets xcodes(version: "xx.x", select_for_current_build_only: true) in the Fastlane file.

[dahlmo]

I'd be happy to write a PR for it, if welcome.

[AntiGuideAkquinet]

While the feature is not added actions like this one can be used to switch to another XCode version.