Mostly fix Python 3.13

[Margen67]

Marked as a draft since onnx 1.18 is currently a prerelease and the build fails on Windows for some reason.
Related: #174

[beveradb]

Thanks! I'll merge anyway for now and either fix or exclude that windows+3.13 combo.
It sounds like it'll probably be resolved by updating Numpy; numpy/numpy#27894

[beveradb]

audio-separator version 0.31 is now released and should work on all platforms with all supported python versions including 3.13 🙏

FYI, I ended up having to fork onnx2torch (https://pypi.org/project/onnx2torch-py313/) to change it to require onnx-weekly instead of onnx for now as otherwise the transitive dependency forced pip to try/fail to build onnx 1.17 on python 3.13 which doesn't work.
Once ONNX 1.18 is fully released and there are wheels for Python 3.13 available on PyPI, I'll delete my onnx2torch-py313 fork/published package and revert audio-separator to using the regular onnx2torch package.