Update torch to >=2.1.0 and fix flash-attn dependency

requirements.txt

@@ -1,4 +1,4 @@
-torch>=2.4.0
+torch>=2.1.0
 torchvision>=0.19.0
 opencv-python>=4.9.0.80
 diffusers>=0.31.0
@@ -11,6 +11,5 @@ easydict
 ftfy
 dashscope
 imageio-ffmpeg
-https://github.com/mjun0812/flash-attention-prebuild-wheels/releases/download/v0.3.18/flash_attn-2.7.4+cu128torch2.8-cp310-cp310-linux_x86_64.whl
-numpy>=1.23.5,<2
-
+flash-attn
+numpy>=1.23.5,<2