Pin pygame version to fix soft_actor_critic (#1412)
Summary:
The latest pygame requires sdl2-config, which is not available in our environment.
Pull Request resolved: https://github.com/pytorch/benchmark/pull/1412
Reviewed By: kit1980
Differential Revision: D43290445
Pulled By: xuzhao9
fbshipit-source-id: 35b4633e4e29449083fe705b8fb6a606117f9dec
