trypag:

conda update pytorch torchvision -c soumith


Oh, so the packages are not sent to the default channels, likewise it was happening for luarocks in Torch.
I would suggest, therefore, to run this command, in order to automate the process.
conda config --add channels soumith


[which] adds the new channel [soumith] to the top of the channel list, making it the highest priority.