Update.md

How to update the generated xcode project after running update.sh

1. Remove VulkanLoader.cpp from videovulkan target source files
2. Remove Mixer.cpp from audioCommon target source files
3. Rename libraries with Dolphin Postfix eg; lzma => 'lzmaDolphin`
4. Change generated xcodeproj main settings to;
   1. Platforms (mac, tvos, ios, visionos plus sims)
   2. Arches => Apple Default
   3. Build active arch only on for Configuration => Debug
   4. Delete these settings from all the subtarget libs so they inherit from root