Attempting to import optlang.inspyred_interface causes error

[DManowitz]

Problem description

Attempting to import optlang.inspyred_interface causes error. This should be importable. I think the call to import interface should be from optlang import interface, as done in other _interface files.

Code Sample

Create a minimal, complete, verifiable example.

import optlang.inspyred_interface

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "...\lib\site-packages\optlang\inspyred_interface.py", line 29, in <module>
    import interface
ModuleNotFoundError: No module named 'interface'

Context

``` >>> optlang.show_versions() Traceback (most recent call last): File "", line 1, in AttributeError: module 'optlang' has no attribute 'show_versions' ```

[cdiener]

That interface has not been update for three years and the inspired package itself looks abandoned so I would suspect it wouldn't even work with the correct import. But if you want to take a stab in repairing we would definitely appreciate this and welcome a PR 😃