docs: clarify supported Python versions in installation section

[hiteshmahajan24]

This PR updates the installation documentation to clarify supported Python versions.

The README previously mentioned Python 3.6+, which is inaccurate. Based on testing, the project works reliably with Python 3.8–3.11, while newer versions (3.12+) may not work due to dependency compatibility issues.

This change improves clarity and helps avoid setup errors for new contributors.

Fixes #1594

What does this PR do, and why?

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Visual changes