Add beta notice

vectorstores/mongovector/doc.go

@@ -1,5 +1,7 @@
 // Package mongovector implements a vector store using MongoDB as the backend.
 //
+// Notice: this packge uses the 2.0.0-beta release of the MongoDB Go Driver.
+//
 // The mongovector package provides a way to store and retrieve document embeddings
 // using MongoDB's vector search capabilities. It implements the VectorStore
 // interface from the vectorstores package, allowing it to be used interchangeably