Update model metadata to set pipeline tag to the new `text-ranking` (#1)

- Update model metadata to set pipeline tag to the new `text-ranking` (338c522bf5c1c4335e46c60ffe0095f12a617b77)


Co-authored-by: Tom Aarsen <tomaarsen@users.noreply.huggingface.co>

README.md

@@ -1,3 +1,4 @@
 ---
 license: cc-by-nc-4.0
+pipeline_tag: text-ranking
 ---