docker mmvc hard coded pytorch and cuda version

[antoinefalisse]

You might want to consider making this line dependent on the args. I had errors when using an image built with ARG PYTORCH="1.9.0" and ARG CUDA="11.1" while keeping the mmvc install line as is. When changed to RUN pip install --no-cache-dir mmcv-full==1.3.17 -f https://download.openmmlab.com/mmcv/dist/cu111/torch1.9.0/index.html, it worked great.

[Czm369]

Thanks for your suggestions.