Dependency Conflict with lib opencv-python and llava-torch

[lunxiaoli66]

As the 4.x versions of opencv-python come out for a while, I found there would be a dependency conflict if install opencv-python==4.x and llava-torch==1.2.2.post1 as for the opencv-python lib, it will require a numpy with version >= 2 while the llava-torch would require a numpy with version~=1.

So I suggest to modify the conda command in README.md from "... opencv-python ..." to " opencv-python==3.x" e.g., "opencv-python==3.4.16.59".

Thanks.