Bug#945389: Tried to upgrade skimage to see whether #945389 is fixed but failed

[Rebecca N. Palmer]

Stefan van der Walt wrote:
> One possibility is that NumPy was compiled with an older version of
> Cython:[...]
> Do you know how I can check the source files for the NumPy 1.17 build
> that is used here?

Source: https://sources.debian.org/src/numpy/1:1.17.4-3/
Build log: https://buildd.debian.org/status/package.php?p=numpy
numpy was built with cython3 0.29.14-0.1.  (Not +b1, but I _think_ "Add 
Python3.8 as supported version" means the ability to run cython3 itself 
in python3.8, not the ability to compile modules for python3.8.)