Update tokenizer_config.json

tokenizer_config.json

@@ -1 +1 @@
-{"bos_token": "[SEP]", "eos_token": "[SEP]", "unk_token": "[UNK]", "sep_token": "[SEP]", "cls_token": "[SEP]", "pad_token": "[PAD]", "mask_token": "[MASK]", "xprophetnet_tokenizer": true}
+{"bos_token": "[SEP]", "eos_token": "[SEP]", "unk_token": "[UNK]", "sep_token": "[SEP]", "pad_token": "[PAD]", "mask_token": "[MASK]", "model_max_length": 512}