`pyproject.toml`: specify dependencies dynamically with `setuptool`

[yunjunz]

Something we might try after this PR: you can specify the dependencies dynamically with newer setuptool. I didn't include it since I wasn't sure how it would interact with PySold's current setuptools version pinning

https://github.com/opera-adt/dolphin/blob/main/pyproject.toml#L23-L34

Originally posted by @scottstanie in #69 (comment)