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

Hello!

## Pull Request overview
* Update metadata to set pipeline tag to the new `text-ranking`

## Changes
This is an automated pull request to update the metadata of the model card. We recently introduced the [`text-ranking`](https://huggingface.co/models?pipeline_tag=text-ranking) pipeline tag for models that are used for ranking tasks, and we have a suspicion that this model is one of them.

Feel free to respond if you have questions or concerns.

- Tom Aarsen

README.md

@@ -2,17 +2,17 @@
 language: multilingual
 license: mit
 tags:
-  - onnx
-  - optimum
-  - text-embedding
-  - onnxruntime
-  - opset19
-  - sentence-similarity
-  - gpu
-  - optimized
+- onnx
+- optimum
+- text-embedding
+- onnxruntime
+- opset19
+- sentence-similarity
+- gpu
+- optimized
 datasets:
-  - mmarco
-pipeline_tag: sentence-similarity
+- mmarco
+pipeline_tag: text-ranking
 ---
 
 # gte-multilingual-reranker-base-onnx-op19-opt-gpu