Automatic signing via `xcodebuild`


Description of the feature request

xcodebuild now supports the use of App Store Connect API keys for authentication with the Apple Developer website. This enables the use of automatic signing via xcodebuild in headless environments, such as build machines and continuous integration setups.

Use case / for what or how I would use it

I would like to use Apple’s automatic signing via xcodebuild.

(optional) Related info - WWDC reference

Signing and Distribution section in Xcode 13 Beta Release Notes.