[hackathon] fix benchmarking script in CONTRIBUTING (#63199)
Summary:
[skip ci]
Per title
Pull Request resolved: https://github.com/pytorch/pytorch/pull/63199
Reviewed By: mruberry
Differential Revision: D30305487
Pulled By: ngimel
fbshipit-source-id: 2704c4f08ab976a55c9f8c2fe54cd4f3f39412cf
