GCP VM from Image example (#5814)

Dockerfile

@@ -59,3 +59,6 @@ ADD https://ultralytics.com/assets/Arial.ttf /root/.config/Ultralytics/
 
 # DDP test
 # python -m torch.distributed.run --nproc_per_node 2 --master_port 1 train.py --epochs 3
+
+# GCP VM from Image
+# docker.io/ultralytics/yolov5:latest