Update requirements.txt

requirements.txt

+pydantic==1.10.9
 pytorch_lightning==1.4.2
 einops
 open-clip-torch
@@ -7,7 +8,7 @@ opencv-python-headless
 scipy
 matplotlib
 lpips
-gradio
+gradio==3.50.2
 chardet
 transformers
 facexlib