[suggestion] Add `open` subcommand

[coffmark]

Thanks for all your maintenance!

I propose to add open subcommand like xcodes open Example.xcodeproj This will open Example.xcodeproj in Xcode version which wrote in .xcode-version

open command (/usr/bin/open) does the same thing, but I would like to specify the Xcode version for each project.

I'm ready to implement and put out a pull request.

I would like to hear your opinion before submitting a pull request.

What do you think?

Thank you!