Update `detectron2` to fix Pillow errors (#1799)
Summary:
As reported in https://github.com/facebookresearch/detectron2/issues/5010, `PIL.Image.LINEAR` no longer exists.
The Pillow requirement in `detectron2` isn't pinned, so old `detectron2` is installing the latest Pillow and causing errors in the TorchBench tests.
Pull Request resolved: https://github.com/pytorch/benchmark/pull/1799
Reviewed By: xuzhao9
Differential Revision: D47928411
Pulled By: msaroufim
fbshipit-source-id: 36fd447475c66c0db643b04cffd1fc8b5d4ca17f
