torch import missed in example

`import torch` is required for `torch.bfloat16` in "How to get Started" section example

README.md

@@ -63,6 +63,7 @@ You can load the model as follows.
 
 ```python
 from transformers import AutoProcessor, AutoModelForImageTextToText
+import torch
 
 model_path = "HuggingFaceTB/SmolVLM2-500M-Video-Instruct"
 processor = AutoProcessor.from_pretrained(model_path)