fix(mongo): correctly type the aggreation pipeline case (#1820)

toucan_connectors/mongo/mongo_connector.py

@@ -119,7 +119,7 @@ def validate_collection(client, database: str, collection: str):
 class MongoDataSource(ToucanDataSource):
     database: str = Field(..., description="The name of the database you want to query")
     collection: str = Field(..., description="The name of the collection you want to query")
-    query: Union[dict, list] = Field(
+    query: Union[dict, list[dict]] = Field(
         {},
         description="A mongo query. See more details on the Mongo " "Aggregation Pipeline in the MongoDB documentation",
     )