update cython to 0.28

[auvipy]

No description provided.

[pv]

It's purposefully old version to check for compatibility.
Is there a reason why it needs to be upgraded?

[ilayn]

Related issues #8581 and linked therein

[rgommers]

no response and not a change we want/need, so closing. thanks @auvipy

[glorioushedgehog]

I don'y know why @auvipy wanted scipy built with Cython 0.28, but I could really use it because of this bug: cython/cython#1953 (comment)
Cython 0.28 fixes it, but I can't find any downloads of scipy built with cypthon 0.28. Is this available anywhere? It would be really great if I could avoid setting up the environment for building scipy on my own.

[andyfaff]

Bumping cython will also be required for supporting Python3.7.

[pv]

Everything in scipy 1.1.0 is already built with Cython 0.28.2, so there's nothing further to do here.

The official locations are https://pypi.org/project/scipy/ and https://github.com/scipy/scipy/releases --- if you are downloading stuff elsewhere, you'll need to deal with the third party from which you are downloading stuff.