Enable support for Python 3.9+

[satta]

This commit basically removes Python 3.10+ language features from the code required to use the python operator in pipelines. This mostly means rewriting code using:

• PEP-604 (Union types written with |)
• PEP-613 (Explicit Type Aliases)
• PEP-634 (Structural Pattern Matching)

We also lower the version requirement in pyproject.toml and update dependencies in poetry.lock.

Tests still succeed:

❯ pyenv exec poetry run pytest
=========================================================================== test session starts ===========================================================================
platform linux -- Python 3.11.2, pytest-8.1.1, pluggy-1.4.0
rootdir: /home/satta/tmp/tenzir/python
configfile: pyproject.toml
plugins: asyncio-0.23.6
asyncio: mode=Mode.AUTO
collected 15 items / 1 skipped                                                                                                                                            

tests/test_convert.py ..                                                                                                                                            [ 13%]
tests/test_utils_arrow.py .............                                                                                                                             [100%]

====================================================================== 15 passed, 1 skipped in 0.25s ======================================================================

If there is anything else to test that you know of, please do so. I have no knowledge of what remains unconvered by pytest.

[dominiklohmann]

I am willing to accept this, but please be aware that we will not restrict ourselves to compatibility with Python 3.9 in the future, as this slows down developers. If as part of future development of the Tenzir Python library someone wants to bump the minimum version, we will allow it.

[satta]

I am willing to accept this, but please be aware that we will not restrict ourselves to compatibility with Python 3.9 in the future, as this slows down developers. If as part of future development of the Tenzir Python library someone wants to bump the minimum version, we will allow it.

TBH once Threat Bus is gone I assume we will quickly update to more recent versions of everything anyway. So I don't worry we will be kept back by this for much longer.