Add Windows setup instructions for native testing

Author: zjwhitehead

platformio.ini

@@ -63,6 +63,11 @@ monitor_filters =
 	time
 monitor_speed = 115200
 
+; Windows setup for native testing - install required packages:
+; winget install MSYS2.MSYS2
+; C:\msys64\usr\bin\bash -l -c "pacman -S --noconfirm mingw-w64-ucrt-x86_64-gcc mingw-w64-ucrt-x86_64-cmake mingw-w64-ucrt-x86_64-ninja"
+; Add C:\msys64\ucrt64\bin to your PATH environment variable
+
 [env:native-test]
 platform = native
 test_framework = googletest