Add evaluation results on the samsum config and test split of samsum

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

@samuel-fipps

, using the predictions stored [here](https://huggingface.co/datasets/autoevaluate/autoeval-eval-samsum-samsum-8a4c42-1554855493).\
Accept this pull request to see the results displayed on the [Hub leaderboard](https://huggingface.co/spaces/autoevaluate/leaderboards?dataset=samsum).\
Evaluate your model on more datasets [here](https://huggingface.co/spaces/autoevaluate/model-evaluator?dataset=samsum).

README.md

@@ -16,19 +16,19 @@ model-index:
     metrics:
     - name: ROUGE-1
       type: rouge
-      value: 50.4987
+      value: 50.5049
       verified: true
     - name: ROUGE-2
       type: rouge
-      value: 25.6888
+      value: 25.6469
       verified: true
     - name: ROUGE-L
       type: rouge
-      value: 41.7283
+      value: 41.7544
       verified: true
     - name: ROUGE-LSUM
       type: rouge
-      value: 46.2626
+      value: 46.2055
       verified: true
     - name: loss
       type: loss