Drop `typing_compat` dependency

[mtitov]

Could this dependency be dropped?
(https://github.com/ExaWorks/psij-python/blob/0.9.8/requirements.txt#L4)

This tool is archived, and if to keep PSI/J updated within the Spack, then need to bring this tool there as well (it is not there right now), but for an archived tool, I would propose to avoid it

[hategan]

Most likely droppable, but we might have to bump the minimum python version to 3.8. Given that 3.7 was EoL-ed, I think that should be reasonable.