Update README.md

Function definition are different in new version of mlx-llm

README.md

@@ -44,7 +44,7 @@ from transformers import AutoTokenizer
 
 model = create_model(
   "e5-mistral-7b-instruct",
-  weights_path="path/to/weights.npz",
+  weights="path/to/weights.npz",
   strict=False
 )