Minimal changes to code and text to work correctly on Paperspace

 - Add pip install --update pip to avoid logging issue in pip 22.x (pypa/pip#11309 (comment))
 - Add text re Paperspace requirements for consistency with other notebook content
 - Remove reference to Graphcore Bow-IPU under "Build training dataset generator", reference IPU-POD16 (note this assumes the notes about throughput remain true)

Author: nmb-paperspace