Re-enable python 2 builds (#31164)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/31164
We have a small number of internal projects that still are on Python 2.
Until we can figure out how to get rid of them, we need to continue
supporting Python 2 for PyTorch.
Test Plan: Imported from OSS
Differential Revision: D18949698
Pulled By: suo
fbshipit-source-id: 4a9d7e4306ed81576e05f243de472937a2bb1176
