Update README to include transformers version requirement

README.md

@@ -122,6 +122,12 @@ model-index:
 ModChemBERT is a ModernBERT-based chemical language model (CLM), trained on SMILES strings for masked language modeling (MLM) and downstream molecular property prediction (classification & regression).
 
 ## Usage
+Install the `transformers` library starting from v4.56.1:
+
+```bash
+pip install -U transformers>=4.56.1
+```
+
 ### Load Model
 ```python
 from transformers import AutoModelForMaskedLM, AutoTokenizer