Fix label correspondence and associated arch

The label correspondence of the model was wrong (giving 34% accuracy on MNLI instead of 82%) and the associated architecture was also wrong.

config.json

@@ -1,7 +1,7 @@
 {
   "activation": "gelu",
   "architectures": [
-    "DistilBertForMaskedLM"
+    "DistilBertForSequenceClassification"
   ],
   "attention_dropout": 0.1,
   "bos_token_id": 0,
@@ -12,14 +12,14 @@
   "hidden_dim": 3072,
   "id2label": {
     "0": "contradiction",
-    "1": "neutral",
-    "2": "entailment"
+    "1": "entailment",
+    "2": "neutral"
   },
   "initializer_range": 0.02,
   "label2id": {
     "contradiction": "0",
-    "neutral": "1",
-    "entailment": "2"
+    "entailment": "1",
+    "neutral": "2"
   },
   "max_position_embeddings": 512,
   "model_type": "distilbert",