cmake: Update build requirements to Xcode 15.1 and macOS 14.2 SDK

Lowest supported macOS version to build(!) macOS will be 13.5 with this
change.

cmake/macos/compilerconfig.cmake

@@ -23,8 +23,8 @@ endif()
 set_property(CACHE CMAKE_OSX_ARCHITECTURES PROPERTY STRINGS arm64 x86_64)
 
 # Ensure recent enough Xcode and platform SDK
-set(_obs_macos_minimum_sdk 13.1) # Keep in sync with Xcode
-set(_obs_macos_minimum_xcode 14.2) # Keep in sync with SDK
+set(_obs_macos_minimum_sdk 14.2) # Keep in sync with Xcode
+set(_obs_macos_minimum_xcode 15.1) # Keep in sync with SDK
 message(DEBUG "macOS SDK Path: ${CMAKE_OSX_SYSROOT}")
 string(REGEX MATCH ".+/MacOSX.platform/Developer/SDKs/MacOSX([0-9]+\\.[0-9])+\\.sdk$" _ ${CMAKE_OSX_SYSROOT})
 set(_obs_macos_current_sdk ${CMAKE_MATCH_1})