Add "sentence-transformers" tag

Hello!

I've set up a `sentence-transformers` tag for datasets that are meant to be used for training/finetuning embedding models, allowing people to easily find datasets that suit their use cases: https://huggingface.co/datasets?other=sentence-transformers
This PR adds your dataset to this list :)

For reference, I link to these datasets at the very bottom of this page: https://sbert.net/docs/sentence_transformer/dataset_overview.html#pre-existing-datasets

- Tom Aarsen

README.md

@@ -6,6 +6,8 @@ language:
 - ar
 size_categories:
 - 10K<n<100K
+tags:
+- sentence-transformers
 ---
 
 # Arabic NLI Triplet