add tzdata to development dependencies

[5j9]

tzdata is used in tests and without it tests fail on windows. Windows users can now run uv run pytest and uv will handle dependencies correctly and all tests pass.

[slashmili]

Thanks for adjustment!

As I don't have windows, unfortunately I can't test it. I tried to run test on windows #173 but it failed because of some unknown timezon.

[5j9]

As I don't have windows, unfortunately I can't test it. I tried to run test on windows #173 but it failed because of some unknown timezon.

That's the error I was referring to. In the test output, click on line 35 where it says tox: py313 to expand the results. Then scroll down until you see: ModuleNotFoundError: No module named 'tzdata'

One way to fix this might be:

1. merge this pull request.
2. in the other pull request which should be on top of this one, In test.yaml, replace python -m pip install --upgrade pip with python -m pip install --upgrade uv
3. in tox.ini, replace python -m unittest discover tests -v with uv run pytest

I've not tested this myself, and while the exact setup may vary, the general approach should work.

Also, I can close this pull request, and we can roll everything into a single one if that works better for you.