Add select option to install

[tahirmt]

Adds options --select and --update to install command.

Details

• Uses #181 as base because without that the --select option will always ask user for password even if the Xcode version is already selected
• I'm not that fluent in PromiseKit so happy to make any improvements
• Creating this as a draft until we can get #181 merged
• Closes #161

[rogerluan]

@tahirmt thank you for this PR! This makes total sense to me 💯

@MattKiazyk this would also be aligned with https://github.com/xcpretty/xcode-install/issues/467, since xcode-install's default behavior automatically selects the Xcode version that was just installed, and it would be a huge improvement over xcode-install and xcodes if we could also optionally run update automatically right before installing (otherwise Xcode versions that exist might not be found). I had to work-around this behavior implementing a "pre-install update" behavior here but it'd be great if it was built-in into xcodes ☺️

I'll review this PR to help move it forward 💪

[rogerluan]

@tahirmt since https://github.com/RobotsAndPencils/xcodes/pull/181 got merged, would you mind rebasing this branch or merging the main branch into this one? 🙇