Add typing_extensions as a dependency. (#42431)
Summary:
Closes gh-38221.
The related pytorch/builder PR: https://github.com/pytorch/builder/pull/475
Pull Request resolved: https://github.com/pytorch/pytorch/pull/42431
Reviewed By: malfet
Differential Revision: D22916499
Pulled By: ezyang
fbshipit-source-id: c8fe9413b62fc7a6b829fc82aaf32531b55994d1
