Create a new DatasetSource.

• dataset_id (str): Required, ID of the dataset. The dataset must already exist.
• source_id (UUID): Required, Unique Identifier(UUID) of the source data. The source must already exist.
• folder (str or None): Optional, Path within the bucket to ingest data from..
• query (str or None): Optional, Query statement to retrieve data.
• created_at (datetime or None): Optional, Timestamp when the data source was created.
• updated_at (datetime or None): Optional, Timestamp when the data source was last updated.
• ingest_type (IngestType): Optional, Type of data ingestion. Default is IngestType.INSERT.