update readme

Former-commit-id: d4eaee262a64e716ce475dc4eb18d8d9697d8dd8

src/llmtuner/hparams/parser.py

@@ -94,6 +94,9 @@ def _check_extra_dependencies(
     if finetuning_args.use_badam:
         require_version("badam", "To fix: pip install badam")
 
+    if finetuning_args.plot_loss:
+        require_version("matplotlib", "To fix: pip install matplotlib")
+
     if training_args is not None and training_args.predict_with_generate:
         require_version("jieba", "To fix: pip install jieba")
         require_version("nltk", "To fix: pip install nltk")