Discuss: Deprecate Python 3.9 support in PyAirbyte

[aaronsteers]

PyAirbyte mostly targets Notebook environments and modern Python runtimes. Although Python 3.9 has not yet hit its End of Life (EOF), we know from PyPi download stats that Python 3.9 usage is extremely low (possibly just from our own CI tests), and we should consider dropping 3.9 support soon so we can focus on newer runtimes like 3.12 and 3.13.

Please chime in below if you have a use case or runtime in mind that still requires Python 3.9