Remove usage of numpy.testing.decorators

Fixes #132 (closed)

enabled an automatic merge when the pipeline for 66954ff4 succeeds

Tested this with numpy 1.18 and everything works.

mentioned in issue bob.ip.tensorflow_extractor#9 (closed)

merged

mentioned in commit b894250b

mentioned in issue bob.pad.base#33 (closed)

mentioned in commit bob.pad.base@53905628

mentioned in merge request bob.pad.base!71 (merged)