PEP425 wheel matching is too strict

[adisbladis]

We should match older python versions, not just the current one. See the priority list in PEP425: https://www.python.org/dev/peps/pep-0425/#id1.

In particular this was a problem with cryptography after https://github.com/pyca/cryptography/issues/5771 where the source build didn't work and setting preferWheel didn't match any wheels, ending up falling back to a source build.

The wheel file cryptography-3.4.4-cp36-abi3-manylinux2014_x86_64.whl should not be filtered out as this is guaranteed to work with newer versions of CPython (as indicated by abi3).