tmpfix(tokenizer_config): force `GPT2TokenizerFast`

tokenizer_config.json

@@ -39,7 +39,7 @@
   "chat_template": "{% for message in messages %}\n{% if message['role'] == 'user' %}\n{{ '<|user|>\n' + message['content'] + eos_token }}\n{% elif message['role'] == 'system' %}\n{{ '<|system|>\n' + message['content'] + eos_token }}\n{% elif message['role'] == 'assistant' %}\n{{ '<|assistant|>\n'  + message['content'] + eos_token }}\n{% endif %}\n{% if loop.last and add_generation_prompt %}\n{{ '<|assistant|>' }}\n{% endif %}\n{% endfor %}",
   "clean_up_tokenization_spaces": true,
   "eos_token": "<|endoftext|>",
-  "tokenizer_class": "GPT2Tokenizer",
+  "tokenizer_class": "GPT2TokenizerFast",
   "model_max_length": 2048,
   "pad_token": "<|endoftext|>",
   "unk_token": "<|endoftext|>"