Docs won't build with cython >=0.29.0 about garnett

[lyrivera]

I'm able to reproduce this error. I'm assuming a quick temporary fix like checking for Cython version on the setup.py file and throw a warning/error if Cython >=0.29.0 would do for now?

[bdice]

@lyrivera Since it only affects the documentation and not the overall function of this package, I don't think we should change anything about this package just yet. The best course of action would be to file a bug with Cython, I can do that at some point but it's not a high priority. Also, if we wait a bit until this package is open-source, then we can just share the source code with the Cython team and it will be easier to debug. I say let's put this on hold for now.

[lyrivera]

@bdice Sounds good

[lyrivera]

Seems like this has been addressed by @klarh on #104. I am now able to build the docs with cython=0.29.0