code review update: cmake ios simulator limitation MacOS 10.15 (#20120)

Author: PatriceJiang

cmake/README.md

@@ -60,7 +60,7 @@ cmake .. -GXcode -DCMAKE_SYSTEM_NAME=iOS -DCMAKE_OSX_SYSROOT=iphoneos
 open Cocos2d-x.xcodeproj
 ```
 
-The parameter `-DCMAKE_OSX_SYSROOT=iphoneos` is optional, it generates a build for running on the iOS device. If you want to run in the simulator, please add `-DCMAKE_OSX_SYSROOT=iphonesimulator`, but remember you can't run a metal-support app in the simulator until Xcode 11.
+The parameter `-DCMAKE_OSX_SYSROOT=iphoneos` is optional, it generates a build for running on the iOS device. If you want to run in the simulator, please add `-DCMAKE_OSX_SYSROOT=iphonesimulator`, but remember you can't run a metal-support app in the simulator until Xcode 11 and MacOS 10.15.
 
 if you want to sign iOS app in CMake, you will need to fill development team ID into `set_xcode_property(${APP_NAME} DEVELOPMENT_TEAM "")`, or select to sign in Xcode after project files generated.
 
@@ -111,4 +111,4 @@ If you want to add cmake build arguments, please add it at [external Native Buil
 
 * CMake Documentation: [cmake.org/documentation](https://cmake.org/documentation/)
 
-* CMake FAQ: [Wiki/CMake_FAQ](https://cmake.org/Wiki/CMake_FAQ)
+* CMake FAQ: [Wiki/CMake_FAQ](https://cmake.org/Wiki/CMake_FAQ)