Notebook Runner uses last release of python package rather than installing from source

[banoffee-pie]

The Jenkins CI runs all the notebooks in /docs to make sure that they are updated (e.g. if any APIs change). However, notebooks using the xmos_ai_tools package install the module from PyPi. This means that the test will run against the latest python package release rather than the source code on the current PR.

This could result in a situation where an API of a module in xmos_ai_tools package is changed in a PR, but the CI incorrectly determines that the notebooks still work.

There should be a separate requirements file for CI that installs the ai_tools package built from the source code on that branch.