Update tox.ini to remove Python 3.8 and change mypy version

[auvipy]

Removed Python 3.8 from envlist and updated mypy basepython to 3.12.

[Copilot]

Pull request overview

This PR removes Python 3.8 from the supported versions in the tox configuration and updates the mypy test environment to use Python 3.12. The removal of Python 3.8 aligns with the codebase's use of PEP 585-style type hints (e.g., dict[str, Any]) which require Python 3.9+. Additionally, the PR fixes a pre-existing typo where mypy was configured to use python3.3 instead of a modern Python version.

Changes:

• Removed Python 3.8 from the tox envlist
• Removed the gh-actions mapping for Python 3.8
• Updated mypy basepython from 3.3 to 3.12 (fixing a typo)

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[Copilot]

There is trailing whitespace at the end of this line. This should be removed for consistency and cleaner formatting.

Suggested change

	python =
	python =