完善README.MD文件 ，完善Unsloth 模型训练方案说明

README.MD

@@ -1229,7 +1229,7 @@ logging.basicConfig(level=logging.INFO)
    
 1. pip install xformers
 2. 获取pytorch+CUDA 依赖包命令：https://pytorch.org/get-started/locally/   命令示例：pip3 install torch torchvision torchaudio --index-url https://download.pytorch.org/whl/cu124
-3. pip install unsloth datasets
+3. pip install unsloth BitsandBytes datasets
 4. triton包安装
    **Windows环境** 
    通过https://huggingface.co/madbuda/triton-windows-builds/tree/main  获取依赖triton包的whl文件安装