requirements.txt: Updated python version >=3.9, <3.12

[HannanNaeem]

Explicitly adding supported python versions in requirements.txt, as the setup or pykokkos is currently incompatible outside this range.

Previously the environment defaulted to the latest python package (at this time 3.12.x), which is not supported.

[jrmadsen]

If there’s a problem with Python 3.12, that probably just means the pybind11 submodule needs to be updated, bc it looks like it hasn’t been updated in 2 years

[HannanNaeem]

I will check it out, thanks!