Update README with Python Version Requirement

[engichang1467]

This PR updates the README to include the minimum Python version requirement (>=3.10), addressing confusion and compatibility issues highlighted in issue #422

Changes include:

• A new section at the beginning of the Installation instructions, guiding users to ensure they have Python 3.10 or later before proceeding with the installation process.
• Instructions for checking the current Python version.
• A note encouraging users to update their Python version if it is below 3.10.

[epwalsh]

As of #426 this shouldn't be necessary. Thank you though!