Pythonnet 3.0.0 is missing python_requires metadata, installs on 3.6

Environment

• Pythonnet version: 3.0.0
• Python version: 3.6.8
• Operating System: Windows 10

Details

• Describe what you were trying to get done.

Pythonnet 3.0.0 is missing python_requires metadata (https://packaging.python.org/en/latest/guides/distributing-packages-using-setuptools/#python-requires) which means that pip will choose this version even with python versions that are not supported.

This creates challenges for owners and users of Python packages that use pythonnet, and still need to support/use Python 3.6.

• What commands did you run to trigger this issue? If you can provide a Minimal, Complete, and Verifiable example this will help us understand the issue.

The following should install pythonnet 2.x but it installs 3.0.0.

$ python3.6 -m pip install pythonnet

• If there was a crash, please include the traceback here.

$ python3.6 -c "import pythonnet"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "C:\Python36\lib\site-packages\pythonnet\__init__.py", line 6, in <module>
    import clr_loader
  File "C:\Python36\lib\site-packages\clr_loader\__init__.py", line 5, in <module>
    from .types import Assembly, Runtime, RuntimeInfo
  File "C:\Python36\lib\site-packages\clr_loader\types.py", line 2, in <module>
    from dataclasses import dataclass, field
ModuleNotFoundError: No module named 'dataclasses'

[filmor]

I pushed it as a post release to keep the version (no code change required).

[filmor]

I’ll yank the existing version and cut a 3.0.1 from master. This will also break for Python 3.11, as the current version doesn’t work with it.