removing async_trait from non async trait in connection.rs (#737)

src/database/connection.rs

@@ -34,7 +34,6 @@ pub trait ConnectionTrait: Sync {
 }
 
 /// Stream query results
-#[async_trait::async_trait]
 pub trait StreamTrait<'a>: Send + Sync {
     /// Create a stream for the [QueryResult]
     type Stream: Stream<Item = Result<QueryResult, DbErr>> + Send;