Added min. version for huggingface_hub

Author: rajatarya

docs/hub/storage-backends.md

@@ -57,7 +57,7 @@ To access a Xet-aware client, add the `hf_xet` Python package when installing `h
 pip install -U huggingface_hub[hf_xet]
 ```
 
-If you use the `transformers` or `datasets` libraries, it's already using `huggingface_hub` so you can simply install `hf_xet` in the same env:
+If you use the `transformers` or `datasets` libraries, it's already using `huggingface_hub` (`huggingface_hub` should be >= 0.30.0) so you can simply install `hf_xet` in the same env:
 
 ```bash
 pip install hf-xet