* Added a tutorial notebook for segmentation. * Updated header for segmentation tutorial and included other YOLOv5 sponsor sections. * Updated segmentation tutorial to match main object detection tutorial. * Update tutorial.ipynb Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com> Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com> Co-authored-by: Ayush Chaurasia <ayush.chaurarsia@gmail.com> Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>