Update model metadata to set pipeline tag to the new `text-ranking`

README.md

@@ -11,7 +11,7 @@ tags:
 base_model: distilbert/distilroberta-base
 datasets:
 - sentence-transformers/quora-duplicates
-pipeline_tag: text-classification
+pipeline_tag: text-ranking
 library_name: sentence-transformers
 metrics:
 - accuracy