fix keys

pubmed-summarization.py

@@ -128,6 +128,6 @@ class PubMedSummarizationDataset(datasets.GeneratorBasedBuilder):
                 'section_names': List[str],
                 'sections': List[List[str]]
                 """
-                article = data["article"]
-                abstract = data["abstract"]
+                article = data["article_text"]
+                abstract = data["abstract_text"]
                 yield id_, {"article": ' '.join(article), "abstract": ' '.join(abstract)}