Use GitHub environment to access to secrets. (#1845)
Summary:
Enhance our security model on managing GitHub secrets
Pull Request resolved: https://github.com/pytorch/benchmark/pull/1845
Reviewed By: huydhn
Differential Revision: D48627756
Pulled By: xuzhao9
fbshipit-source-id: 2245d9c3334c2b9a09038e7611723a8a6e0553b5
