Add different version branches. #34
Description
When I use RT-Thread, it has different version branches that I can easily clone and use, which is very convenient.
However, RT-Thread needs to be used with env or env-windows, and env-windows only has a main branch with tags to mark versions.
As is well known, different versions of RT-Thread must be used with corresponding versions of env-windows.
Therefore, I hope that version branches can be created for env-windows as well, making it easier to clone according to specific versions.