Bug#997081: statsmodels FTBFS - tests fail

[Rebecca N. Palmer]

Reproduced here; not obviously known upstream.  Autopkgtest says it 
started between 2021-08-30 and 2021-09-14 in unstable, between 
2021-10-10 and 2021-10-18 in testing.

It might be easiest to upgrade to 0.13.0 (if it fixes this - I haven't 
checked yet), given that we should do that anyway at some point, but 
that involves testing whether it breaks any rdeps.