Update README.md

typo fix

Author: mingxzhao

docs/lab-4/README.md

@@ -280,7 +280,7 @@ ilab model train --pipeline simple
 4) When this is completed, you'll need to test this model, which is the following command:
 
 ```bash
-lab model test --model-dir ~/.local/share/instructlab/instructlab-granite-7b-lab --adapter-file ~/.local/share/instructlab/checkpoints/instructlab-granite-7b-lab-mlx-q/adapters-100.npz --data-dir ~/.local/share/instructlab/datasets
+ilab model test --model-dir ~/.local/share/instructlab/instructlab-granite-7b-lab --adapter-file ~/.local/share/instructlab/checkpoints/instructlab-granite-7b-lab-mlx-q/adapters-100.npz --data-dir ~/.local/share/instructlab/datasets
 ```
 
 5) Now to run the command on the Mac M3, or Apple hardware you'll need to convert it to a `gguf`, that is this next command.