`numpy.testing.decorators.setastest` is no longer available in the latest `numpy 1.18`

Updating to numpy version 1.18 breaks this package as the import https://gitlab.idiap.ch/bob/bob.bio.base/blob/33b527af1418dff1812e2613d91f55b6e8ee61c8/bob/bio/base/database/database.py#L8 fails.

Workarounds:

1. Use numpy version 1.17
2. Remove this import and its later use.

I have currently no solution how to replace the functionality of numpy.testing.decorators.setastest, though.