Bug#1013086: python-bayespy: tests fail using deprecated scipy.optimize.optimize

[Drew Parsons]

Source: python-bayespy
Version: 0.5.22-1
Severity: serious
Tags: upstream
Justification: debci

bayespy tests use scipy.optimize.optimize which is deprecated and no
longer has attribute _epsilon.

Hence bayespy tests fail with scipy 1.8.1