There might be issues with torchtext, since it was changing a lot during this course.
Please use PyTorch 1.9.0 and TorchText 0.9.0 for all of the notebooks to work.
You can also try pip3 install --pre torch torchvision torchaudio -f https://download.pytorch.org/whl/nightly/cu111/torch_nightly.html which might fix, but again this is nightly and it changes a lot as well.
This fixed it:
! pip install torch==1.8.1+cu102 torchtext==0.9.0 -f https://download.pytorch.org/whl/torch_stable.html