README: update version description
README: update version description

andelf/rust-sdl2_mixer,Rust-SDL2/rust-sdl2,Cobrand/rust-sdl2,vadixidav/rust-sdl2,Cobrand/rust-sdl2,AngryLawyer/rust-sdl2,Cobrand/rust-sdl2,Rust-SDL2/rust-sdl2,crumblingstatue/rust-sdl2_mixer,Rust-SDL2/rust-sdl2