Add evaluation results on the plain_text config of squad

Beep boop, I am a bot from Hugging Face's automatic model evaluator 👋!\
Your model has been evaluated on the plain_text config of the [squad](https://huggingface.co/datasets/squad) dataset by

@nbroad

, using the predictions stored [here](https://huggingface.co/datasets/autoevaluate/autoeval-eval-project-squad-4b228794-1283349088).\
Accept this pull request to see the results displayed on the [Hub leaderboard](https://huggingface.co/spaces/autoevaluate/leaderboards?dataset=squad).\
Evaluate your model on more datasets [here](https://huggingface.co/spaces/autoevaluate/model-evaluator?dataset=squad).

README.md

@@ -55,6 +55,23 @@ model-index:
       type: f1
       value: 79.3321
       verified: true
+  - task:
+      type: question-answering
+      name: Question Answering
+    dataset:
+      name: squad
+      type: squad
+      config: plain_text
+      split: validation
+    metrics:
+    - name: Exact Match
+      type: exact_match
+      value: 81.8604
+      verified: true
+    - name: F1
+      type: f1
+      value: 89.6654
+      verified: true
 ---
 
 xtremedistil-l12-h384 trained on SQuAD 2.0