Drop python2 support for python-ipython_genutils

Summary:
Packager notes:
Both python-traitlets and python-qtconsole are built with python3.

Signed-off-by: Algent Albrahimi <algent@protonmail.com>

Test Plan: Run a few python scripts using spyder3.

Reviewers: Triage Team, JoshStrobl

Reviewed By: Triage Team, JoshStrobl

Subscribers: JoshStrobl

Differential Revision: https://dev.getsol.us/D9972