[llvm] [libclang/python] Change minimum Python test version to 3.8 (PR #95210)

[Jannick Kremer via llvm-commits]

DeinAlptraum wrote:

I don't quite understand how the concurrency-cancelling thing works, but it seems that the test for 3.8 was cancelled... would be surprised if this fails, but just in case it would be nice if one of you could restart the bindings 3.8 test

https://github.com/llvm/llvm-project/pull/95210