Add evaluation results on the default config and test split of multi_news

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

@pszemraj

, using the predictions stored [here](https://huggingface.co/datasets/autoevaluate/autoeval-eval-multi_news-default-e22c67-2252871793).\
Accept this pull request to see the results displayed on the [Hub leaderboard](https://huggingface.co/spaces/autoevaluate/leaderboards?dataset=multi_news).\
Evaluate your model on more datasets [here](https://huggingface.co/spaces/autoevaluate/model-evaluator?dataset=multi_news).

README.md

@@ -342,6 +342,39 @@ model-index:
       type: gen_len
       value: 222.6626
       verified: true
+  - task:
+      type: summarization
+      name: Summarization
+    dataset:
+      name: multi_news
+      type: multi_news
+      config: default
+      split: test
+    metrics:
+    - name: ROUGE-1
+      type: rouge
+      value: 38.7332
+      verified: true
+    - name: ROUGE-2
+      type: rouge
+      value: 11.0072
+      verified: true
+    - name: ROUGE-L
+      type: rouge
+      value: 18.6018
+      verified: true
+    - name: ROUGE-LSUM
+      type: rouge
+      value: 34.5911
+      verified: true
+    - name: loss
+      type: loss
+      value: 3.5744354724884033
+      verified: true
+    - name: gen_len
+      type: gen_len
+      value: 192.0014
+      verified: true
 ---
 
 # Longformer Encoder-Decoder (LED) for Narrative-Esque Long Text Summarization