specify the working transformers version

README.md

@@ -35,6 +35,7 @@ llava-internlm2-7b is a LLaVA model fine-tuned from [InternLM2-Chat-7B](https://
 
 ```shell
 pip install -U 'xtuner[deepspeed]'
+pip install transformers==4.38.0 # Up-to-date version does not work
 ```
 
 ### Chat