Pin torchvision version. (#20811)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/20811
ghimport-source-id: 52e043453272d8441a2c0efd7f005b71ded024d6
Differential Revision: D15779416
Pulled By: ezyang
fbshipit-source-id: 1b3c2d9aeab57e580038f0c2a8bfbfcae9d7b62a
