use libpython3-dev instead of libpython3.8-dev

[altendky]

https://github.com/Chia-Network/chiavdf/actions/runs/3888384319/jobs/6635642471#step:3:16

E: Package 'libpython3.8-dev' has no installation candidate

I suspect that this broke with the transition of ubuntu-latest runners from Ubuntu 20.04 to 22.04. Unless we need 3.8 specifically then let's just take whatever the Ubuntu is giving us, or explicitly matrix across 'all' versions.

Draft for:

• asking around for reasons we might need to be testing with 3.8 specifically

[hoffmang9]

In the past this could pull 3.6 and not 3.7+. Should be fine now.

[arvidn]

@altendky libpython3 sounds like it might implement abi3 rather than version specific python. If it works, it sounds like an improvement for sure.

[altendky]

I don't think that's related here. I think libpython3-dev is just the dev headers etc for the default Python 3 version rather than specifically the Python 3.8 version (that no longer is provided on the runner). Also, this is just changing for the workflow that builds against optimizations and sanitization options for testing.