Add automated Python version update workflow

[hashhar]

Description

Add a scheduled GitHub Action that keeps the project's Python version support matrix and metadata up to date without manual PRs.

Non-technical explanation

Release notes

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* Fix some things. ({issue}`issuenumber`)

[Copilot]

Pull request overview

Adds a scheduled GitHub Action to automatically update the repository’s supported Python version metadata (packaging classifiers, CI matrices, and tooling config) based on the official Python release cycle data.

Changes:

• Introduces a monthly scheduled + manually triggerable workflow that runs an update script and opens/updates a PR from a bot branch.
• Adds a Python script that fetches Python’s release-cycle JSON and updates setup.py, tox.ini, CI/release workflows, README, and pre-commit config accordingly.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

File	Description
.github/workflows/update-python-versions.yml	New scheduled workflow to run the updater, push a bot branch, and create/update a PR.
.github/scripts/update_python_versions.py	New updater script that fetches Python lifecycle data and rewrites version-related config across the repo.

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