[clang] [libclang/python] Bump minimum compatibility to Python 3.6 (PR #77228)

[Craig Hesling via cfe-commits]

linux4life798 wrote:

> This should just bump to 3.8 IMO. Anything below that is end-of-life and a waste of time to support.

I agree and my personal plan is still to bump the version to 3.7 or 3.8, but it was more important to me to make progress towards adding any usable type annotations than it is to raise the min python version across llvm or just within libclang. I figured this incremental change was safe, couldn't be blocked based on min version, and doesn't introduce any syntax that has been obsoleted in later python.

Let me know if you think there is something I could do to help progress the transition to python min version 3.8 (or 3.7).

https://github.com/llvm/llvm-project/pull/77228