Update pull_request.paths filter in workflows for switch from setup.py to pyproject.toml

[matt-graham]

The tests and documentation Action workflows both uses path filters to only trigger when a subset of files in repository are changed in a pull-request. For both there is currently a specific entry for files matching setup.* which matched both the setup.py and setup.cfg files previously present before #1158 was merged:

TLOmodel/.github/workflows/docs.yml

Line 14 in f88df3e

- setup.*

TLOmodel/.github/workflows/tests.yml

Line 14 in f88df3e

- setup.*

These should be changed to pyproject.toml or similar to ensure we trigger the workflows whenever this file is changed.