feat: add support for Python 3.13

[omercnet]

Introduce support for Python 3.13 in the CI workflow, dependency specifications, and tox environment configurations to ensure compatibility with the latest Python version.

fixes https://github.com/descope/etc/issues/11180

[Copilot]

Pull Request Overview

Add Python 3.13 support across CI, tox environments, and package metadata.

• Extend tox env list and GitHub Actions matrix to include Python 3.13
• Update pyproject classifiers to advertise Python 3.13
• Map Python 3.13 to the py313 tox environment in the [gh] section

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
tox.ini	Added py3{13,…} to env_list and GH mapping
pyproject.toml	Included Python 3.13 in the classifiers list
.github/workflows/ci.yml	Added Python 3.13 to the test matrix

Comments suppressed due to low confidence (2)

tox.ini:49

• [nitpick] Ensure the indentation of this line matches the other entries under the [gh] python mapping to prevent parsing errors (align with the same number of spaces as the existing lines).

    3.13 = py313, type, format

tox.ini:8

• The tox env list includes Python 3.8 and 3.9, but the CI matrix and classifiers only target 3.10+. Please align supported Python versions across tox.ini, CI workflow, and pyproject.toml (either remove older ones or add them to CI and classifiers).

    py3{13, 12, 11, 10, 9, 8}

[github-actions]

Coverage report

The coverage rate went from 97.67% to 97.67% ⬇️

None of the new lines are part of the tested code. Therefore, there is no coverage data about them.