Small release with a few new features

Enhancements and Changes

• Minimum Python version now 3.9
• Update library dependencies, including allowing numpy 2.0
• New convert_cached_image() and convert_cached_shape() methods

Closed Issues

• Issue #420 - new convert_cached_image() and convert_cached_shape() methods
• Issue #441 - improve error message when sketch file is executed without ever being saved
• Issue #443 - repairing the Py5Image.copy() method
• Issue #446 - unpin numpy, allowing py5 to be installed alongside numpy 2.0
• Issue #447 - repairing and enhancing set_println_stream(). This change was needed to support the future project py5ascii.