[MacPorts] #69668: Use newer Xcode on macOS 14 GitHub Actions runner

[MacPorts]

#69668: Use newer Xcode on macOS 14 GitHub Actions runner
----------------------------+---------------------
 Reporter:  ryandesign      |      Owner:  admin@…
     Type:  defect          |     Status:  new
 Priority:  Normal          |  Milestone:
Component:  server/hosting  |    Version:
 Keywords:                  |       Port:
----------------------------+---------------------
 On the macOS 14 GitHub Actions runner building MacPorts base it says:

 {{{
 checking Xcode location...
 /Applications/Xcode_15.0.1.app/Contents/Developer
 }}}

 {{{
 Warning: The installed version of Xcode (15.0.1) is known to cause
 problems. Version 15.1 or later is recommended on macOS 14.
 }}}

 When building a port it says:

 {{{
 DEBUG: Xcode 15.0.1, CLT 15.3.0.0.1.1708646388
 }}}

 Can we switch to a newer Xcode?

-- 
Ticket URL: <https://trac.macports.org/ticket/69668>
MacPorts <https://www.macports.org/>
Ports system for macOS