Fix hyphens to underscores in sam2 branch (#665)

Author: guajun

label_studio_ml/examples/segment_anything_2_image/README.md

@@ -149,7 +149,7 @@ You should now have the following folder structure:
 
 ```bash
 cd ~/sam2
-label-studio-ml start ../label-studio-ml-backend/label-studio-ml/examples/segment_anything_2_image
+label-studio-ml start ../label-studio-ml-backend/label_studio_ml/examples/segment_anything_2_image
 ```
 
 Due to breaking changes from Meta [HERE](https://github.com/facebookresearch/sam2/blob/c2ec8e14a185632b0a5d8b161928ceb50197eddc/sam2/build_sam.py#L20), it is CRUCIAL that you run this command from the sam2 directory at your root directory.