Change StreamTarget batch size to 1 (#271)

Co-authored-by: Dina Nimrodi <[email protected]>

storey/targets.py

@@ -585,7 +585,7 @@ class StreamTarget(Flow, _Writer):
     :type storage_options: dict
     """
 
-    def __init__(self, storage: Driver, stream_path: str, sharding_func: Optional[Callable[[Event], int]] = None, batch_size: int = 8,
+    def __init__(self, storage: Driver, stream_path: str, sharding_func: Optional[Callable[[Event], int]] = None, batch_size: int = 1,
                  columns: Optional[List[str]] = None, infer_columns_from_data: Optional[bool] = None, **kwargs):
         kwargs['stream_path'] = stream_path
         kwargs['batch_size'] = batch_size