XCode 16 buildable folders don't work with Slather

[andrevinic]

When you try to use buildable folders, the new feature of XCode 16, it doesn't work for Slather, it says it can't generate the code coverage command "Exit status of command 'slather coverage --html --output-directory...".

[cah-iswaria-sasi]

even we are facing this issues with xcode 16, whats the fix? xcodeproj gem in github has latest release 1.27.0 but slather mentioned xcodeproj 1.27.1? How

@ksuther @jarrodlombardo-EventBase