Implement pip-tools dependency management

[bskinn]

• [ ] Documentation
  • Updating CONTRIBUTING.md
  • Checking if anything else needs updating
• [ ] Tests
• [ ] CHANGELOG

[bskinn]

And, we immediately hit the problem of the pinned dependency versions based on Python 3.10 not being compatible with 3.8.

If it can even be resolved at all, it's likely to cause more problems than it solves. Closing as nuh-uh.