[Bugfix] Use RayActorError for older versions of Ray in RayTokenizerG…

…roupPool (vllm-project#6039)

vllm/transformers_utils/tokenizer_group/ray_tokenizer_group.py

@@ -2,7 +2,11 @@
 import os
 from typing import List, Optional
 
-from ray.exceptions import ActorDiedError
+try:
+    from ray.exceptions import ActorDiedError
+except ImportError:
+    # For older versions of Ray
+    from ray.exceptions import RayActorError as ActorDiedError
 from ray.util.scheduling_strategies import NodeAffinitySchedulingStrategy
 from transformers import PreTrainedTokenizer