Support python13

[LeoGrin]

Fix #234

[noahho]

Amazing! Just take a look at the requirements spec

[noahho]

Shouldn't this be <= 3.13 as we aren't testing newer versions?

[LeoGrin]

See some discussion in #234, I changed my mind and now think it makes sense not to upper bound the python version. WDYT?

Pull Request Overview

This PR adds support for Python 3.13 by updating workflow configurations, modifying package metadata, adjusting tests, and updating the README badge and compatibility statement.

• Updated GitHub Actions workflows to use Python 3.13 and conditionally install onnx.
• Modified pyproject.toml to remove the upper bound on supported Python versions and added Python 3.13 to classifiers.
• Updated tests and README to reflect Python 3.13 support.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
.github/workflows/pull_request.yml	Update of python-version and conditional installation for onnx.
pyproject.toml	Adjustment of requires-python constraint and classifiers update.
tests/test_classifier_interface.py	Added xfail for onnx export tests on python3.13.
tests/test_regressor_interface.py	Added xfail for onnx export tests on python3.13.
README.md	Updated badge and compatibility list to include Python 3.13.

Comments suppressed due to low confidence (2)

.github/workflows/pull_request.yml:82

• Ensure that the comparison against '3.13' correctly handles potential variations in how the Python version might be represented (e.g., '3.13.0'); consider normalizing the version string before comparison.

if [[ "${{ matrix.python-version }}" != "3.13" ]]; then

pyproject.toml:17

• By removing the upper bound on the Python version, the package may be installed on versions that are not fully supported (e.g., potential issues with onnx on Python 3.13). Consider documenting this behavior clearly in the release notes or adjusting the requirement if appropriate.

requires-python = ">=3.9"