fix: pin gradio version to prevent file route redirect vulnerability

Pin gradio to >=4.0,<5.0 to avoid the open redirect vulnerability
in gradio 6.x file serving route. Fixes #160.

Author: LauraGPT

requirements.txt

@@ -4,7 +4,7 @@ scikit-learn>=1.3.2
 funasr>=1.1.2
 moviepy==1.0.3
 numpy==1.26.4
-gradio
+gradio>=4.0,<5.0
 modelscope
 torch>=1.13
 torchaudio