add missing model type

This adds the missing `model_type` to load the model with `AutoModelForSequenceClassification`

config.json

@@ -14,6 +14,7 @@
   },
   "attention_probs_dropout_prob": 0.1,
   "hidden_act": "gelu",
+  "model_type": "bert",
   "hidden_dropout_prob": 0.1,
   "hidden_size": 768,
   "initializer_range": 0.02,