Suppress `pretrained` warnings from torchvision (#1280)
Summary:
Pull Request resolved: https://github.com/pytorch/benchmark/pull/1280
Torchvision has deprecated the `pretrained=...` in favor for `weights=WEIGHTS_ENUM`
Before:
```
warnings.warn(
/data/users/dberard/vision/torchvision/models/_utils.py:208: UserWarning: The parameter 'pretrained' is deprecated since 0.13 and may be removed in the future, please use 'weights' instead.
warnings.warn(
/data/users/dberard/vision/torchvision/models/_utils.py:223: UserWarning: Arguments other than a weight enum or `None` for 'weights' are deprecated since 0.13 and may be removed in the future. The current behavior is equivalent to passing `weights=VGG16_Weights.IMAGENET1K_V1`. You can also use `weights=VGG16_Weights.DEFAU LT` to get the most up-to-date weights.
```
Test Plan: Imported from OSS
Reviewed By: xuzhao9
Differential Revision: D41098357
Pulled By: davidberard98
fbshipit-source-id: bf7873c95b29722dbcebf02b9f67d062e009a078
