Remove unused future dependency

[musicinmybrain]

(not to be confused with from __future__ import …)

future will not be buildable, installable and usable with Python 3.13, which removes lib2to3 and 2to3.

[uniqueg]

Test fails likely because of this.

[musicinmybrain]

Perhaps it would be better to migrate https://github.com/ohsu-comp-bio/py-tes/blob/master/.github/workflows/tests.yml to use pytest instead? As you are seeing, nose has not been maintained for something like eight years, and it is no longer compatible with current Python versions.