Drop Python 3.9 support and bump minimum required version to Python 3.10

[YagoMCastro]

Python 3.9 will reach end-of-life on October 31, 2025. We should update Magali to drop support for Python 3.9 and make Python 3.10 the new minimum required version. It aligns Magali with other Fatiando projects, ensuring consistent environment support and simplifying dependency management.