新增pitch增强的底模，在"pitch_xxxk"目录下.

将名为"model_0.pt"的预训练模型, 放到config内"expdir: exp/*****"参数指定的模型导出文件夹内, 没有就新建一个, 程序会自动加载该文件夹下的预训练模型.

Add a "pitch" enhanced pre training model in the "pitch_xxxk" directory.

Move the pre-trained model named "model_0. pt" to the model export folder specified by the "expdir: exp/******" parameter in config, and the program will automatically load the pre-trained models in that folder.