It should be possible to ship less wheels

Since I'm looking into these things for something else and I've noticed there are a lot of wheels for this module, I figured I'd dump this information here:
it is possible to build with `setup.py bdist_wheel --py-limited-api=cp36`, in which case you end with cp36-abi3 wheels that can be installed by any version >= 3.6.

Start with setup.py and the existing wheel build configuration. Run the documented bdist_wheel command with --py-limited-api=cp36, then verify that the resulting cp36-abi3 wheels are installable on Python versions >= 3.6 and that fewer wheel variants are produced.

Written by the indexing model from the issue text.