Doesn't build on py39

[mariusvniekerk]

There was a change in cpython which means that the cython bits need to be regenerated

src/spavro/fast_binary.c:29031:74: error: no member named 'tp_print' in 'struct _typeobject'

[mikepk]

I can't merge the pull request (or close the issue), but I've done the same build over on my fork of Spavro https://github.com/mikepk/spavro and it passes all tests - including py 3.9. I published it to pypi as v 1.1.24. I don't think Pluralsight wants to own this anymore - I'm currently checking with them (as the author I've been the only maintainer and I haven't been employed there for a while).