CMake 3.26.4 warns that RapidJSON's minimum version needs to be raised

[KenSykes]

This is with cmake 3.26.4:

CMake Deprecation Warning at build/kk/vcpkg_installed/x64-windows/share/rapidjson/RapidJSONConfig.cmake:3 (cmake_minimum_required):
  Compatibility with CMake < 3.5 will be removed from a future version of
  CMake.

 

  Update the VERSION argument <min> value or use a ...<max> suffix to tell
  CMake that the project does not need compatibility with older versions.

[the-moisrex]

We need to update the version.