Modify Python versions in tests workflow

[auvipy]

Updated Python version from 'pypy-3.9' to 'pypy-3.11' in workflow.

[Copilot]

Pull request overview

This PR updates the Python version matrix in the GitHub Actions test workflow. The change removes Python 3.8 and pypy-3.9 from testing, and adds pypy-3.11 to modernize the PyPy testing version.

Changes:

• Removed Python 3.8 from the test matrix
• Upgraded PyPy version from pypy-3.9 to pypy-3.11

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[Copilot]

Removing Python 3.8 from the test matrix creates inconsistency with other configuration files in the repository. The setup.cfg file still declares support for Python 3.8 in its classifiers (line 20) and python_requires is set to >=3.6 (line 34). Additionally, tox.ini still includes py38 in its envlist and gh-actions mapping. If Python 3.8 support is being dropped, these other files should be updated as well. Alternatively, if Python 3.8 support should be maintained, it should remain in the test matrix.

Suggested change

	python-version: ['3.9', '3.10', '3.11', '3.12', 'pypy-3.11']
	python-version: ['3.8', '3.9', '3.10', '3.11', '3.12', 'pypy-3.11']