Update tokenizer_config.json

Modify model_max_length to 4096 instead of 512

tokenizer_config.json

@@ -52,7 +52,7 @@
   "cls_token": "[CLS]",
   "do_lower_case": true,
   "mask_token": "[MASK]",
-  "model_max_length": 512,
+  "model_max_length": 4096,
   "pad_token": "[PAD]",
   "sep_token": "[SEP]",
   "strip_accents": null,