Bump torch>=1.8.0 and torchvision>=0.9.0 (#11970)

README.md

@@ -78,8 +78,8 @@ See the [YOLOv5 Docs](https://docs.ultralytics.com/yolov5) for full documentatio
 <summary>Install</summary>
 
 Clone repo and install [requirements.txt](https://github.com/ultralytics/yolov5/blob/master/requirements.txt) in a
-[**Python>=3.7.0**](https://www.python.org/) environment, including
-[**PyTorch>=1.7**](https://pytorch.org/get-started/locally/).
+[**Python>=3.8.0**](https://www.python.org/) environment, including
+[**PyTorch>=1.8**](https://pytorch.org/get-started/locally/).
 
 ```bash
 git clone https://github.com/ultralytics/yolov5  # clone