Fix Llama 3.2 tokenizer (#1772)

Author: rasbt

litgpt/tokenizer.py

@@ -94,7 +94,7 @@ def check_if_bos_token_used(self, checkpoint_dir: Path) -> bool:
             config = json.load(fp)
         # for LlaMA-3 tokenizer there is no `add_bos_token` at all and `tokenizer_class` is only
         # `PreTrainedTokenizerFast`
-        if checkpoint_dir.stem.startswith("Meta-Llama-3"):
+        if checkpoint_dir.stem.startswith(("Meta-Llama-3", "Llama-3")):
             return True
         if "add_bos_token" in config:
             return config["add_bos_token"]