cppwinrt: VS2019 16.9 compile error: implement pre-C++20 coroutine support. Use for standard C++20 coroutines

I have a UWP/cppwinrt project which I build with CMake. In the latest VS2019 Version 16.9.0 I am unable to compile:

C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.28.29910\include\experimental\coroutine(37,1): fatal error C1189: #error:  The <experimental/coroutine> and <experimental/resumable> headers are only supported with /await and implement pre-C++20 coroutine support. Use <coroutine> for standard C++20 coroutines. (compiling source file C:\Users\Application_UWP.cpp) 
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.28.29910\include\experimental\coroutine(37,1): fatal error C1189: #error:  The <experimental/coroutine> and <experimental/resumable> headers are only supported with /await and implement pre-C++20 coroutine support. Use <coroutine> for standard C++20 coroutines. (compiling source file C:\Users\Application_Impl_UWP.cpp) 
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.28.29910\include\experimental\coroutine(37,1): fatal error C1189: #error:  The <experimental/coroutine> and <experimental/resumable> headers are only supported with /await and implement pre-C++20 coroutine support. Use <coroutine> for standard C++20 coroutines. (compiling source file C:\Users\Application.cpp)