Update requirements.txt

backend/requirements.txt

@@ -45,7 +45,7 @@ fake-useragent==1.5.1
 chromadb==0.6.2
 pymilvus==2.5.0
 qdrant-client~=1.12.0
-opensearch-py==2.7.1
+opensearch-py==2.8.0
 
 
 transformers