Add sentence-transformers library name

Hello!

## Pull Request overview
* Add sentence-transformers library name

## Details
This allows this model to be freely available over Inference API and in the Widget like this:


- Tom Aarsen

README.md

@@ -12,7 +12,7 @@ license: apache-2.0
 model-index:
 - name: sentence-flaubert-base by Van Tuan DANG
   results:
-  - task: 
+  - task:
       name: Sentence-Embedding
       type: Text Similarity
     dataset:
@@ -20,9 +20,10 @@ model-index:
       type: stsb_multi_mt
       args: fr
     metrics:
-       - name: Test Pearson correlation coefficient
-         type: Pearson_correlation_coefficient
-         value:  87.14
+    - name: Test Pearson correlation coefficient
+      type: Pearson_correlation_coefficient
+      value: 87.14
+library_name: sentence-transformers
 ---
 
 ## Pre-trained sentence embedding models are the state-of-the-art of Sentence Embeddings for French.