Update README.md

[Dimi8146]

VS Redistributable is not the only prereq, the build tools that come with a full Visual Studio installation are also required, as well as most of the recommended optional features. This is not noticeable on the developer's machine, only reproducible from a fresh one.

I have attached a log for proof.
Error log, post-discovery & pre-fix
Excerpt:

error: linker `link.exe` not found
  |
  = note: program not found

note: the msvc targets depend on the msvc linker but `link.exe` was not found

note: please ensure that Visual Studio 2017 or later, or Build Tools for Visual Studio were installed with the Visual C++ option.

note: VS Code is a different product, and is not sufficient.

https://stackoverflow.com/questions/55603111/unable-to-compile-rust-hello-world-on-windows-linker-link-exe-not-found

This was my powershell script to setup RGB on windows (drop the .txt extension)

This can be slimmed down with msys2 if I understand correctly. Will be investigating.

[dr-orlovsky]

Thank you very much for figuring that out!