* Add PyTorch Hub classification CI checks

Add PyTorch Hub loading of official and custom trained classification models to CI checks. 

May help resolve https://github.com/ultralytics/yolov5/issues/8790#issuecomment-1219840718Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Update hubconf.py
Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>
Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>