README.md: update faq about runtime.LockOSThread and multi-threading
README.md: update faq about runtime.LockOSThread and multi-threading

Signed-off-by: Lilis Iskandar <3de94fd28d904a22098fd49f2d9af76f176c5fe9@protonmail.com>

veandco/go-sdl2,veandco/go-sdl2