[llvm] [python] Bump Python minimum version to 3.8 (PR #78828)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

Seems like that's a MLIR Python dependency?

Numpy gets installed here in the Buildkite CI:
https://github.com/google/llvm-premerge-checks/blob/ff879c8fa1af8f06c8cb2ac7707ceef52965e87e/scripts/steps.py#L136

I wonder if there are multiple versions of Python on the windows runner and the default one isn't the 3.9.7 where the dependencies are getting installed.


https://github.com/llvm/llvm-project/pull/78828