CUDA version in debian/sid is not new enough for users

[M. Zhou]

Hi anbe,

The current version of nvidia-cuda-toolkit is 12.4 and 12.5 in experimental.
But That's still older than the oldest CUDA version used by pytorch 
binary releases[2].
According to the cuda compatibility matrix, it seems there is no problem 
for the
current driver package to support CUDA 12.6 [1].

A lagging CUDA version makes me less motivated to maintain pytorch-cuda etc.
Do you have any plan on this? If there is no specific reason, I can get back
to co-maint the nvidia-cuda-toolkit to accelerate a bit.

[1] 
https://docs.nvidia.com/deploy/cuda-compatibility/latest/minor-version-compatibility.html
[2] https://pytorch.org/ (cuda 12.6 is the oldest)