build: replace support of python '3.6' with python '3.13'

[zimeg]

Summary

This PR drops support of Python 3.6 and adds support for Python 3.13.

Notes

• 📚 https://slack.dev/python-development-at-slack/
• 🔍 Found in CI failures of: ci: pin actions workflow step hashes and use minimum permissions #110

Requirements

• I've read and understood the Contributing guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[WilliamBergamin]