Deprecation warnings in Codespaces

[StevenMaude]

2023-11-28 10:00:47.216 [error] Following setting is deprecated: "python.linting.flake8Enabled"
2023-11-28 10:00:47.216 [error] All settings starting with "python.linting." are deprecated and can be removed from settings.
2023-11-28 10:00:47.216 [error] Linting features have been moved to separate linter extensions.
2023-11-28 10:00:47.216 [error] See here for more information: https://code.visualstudio.com/docs/python/linting
2023-11-28 10:00:47.216 [error] Please install "flake8" extension: https://marketplace.visualstudio.com/items?itemName=ms-python.flake8

We might also want to review what we use here; maybe Ruff would be better?

Also see #52.

[StevenMaude]

Fixed by #119.