move detectron2 pin to the most recent tip (#2272)
Summary:
With the existing pin, cpp extension compilation on ROCm fails.
# Testing
`$ pip install --user --verbose -r torchbenchmark/util/framework/detectron2/requirements.txt`
(ensure the extension is successfully built)
Pull Request resolved: https://github.com/pytorch/benchmark/pull/2272
Reviewed By: davidberard98
Differential Revision: D57938441
Pulled By: xuzhao9
fbshipit-source-id: 87f9e131b066a969c8c48afd692639363bddc4a0
