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` (415ecb77f4d834f4eba7545291ada41fd3d3e16f)


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

README.md

@@ -5,6 +5,7 @@ language:
 license: mit
 base_model:
 - google/bert_uncased_L-2_H-128_A-2
+pipeline_tag: text-ranking
 ---
 
 ```python