- Introduced support for both `.yml` and `.yaml` config file extensions. Previously it was only `.yaml`.
- Implemented lists as possible placeholder values. Previously only scalar values were supported.
- Changed default values for `FileFormat.format_options`, `User.session_params`, `Warehouse.warehouse_params` from `None` to `{}`. It should help to prevent errors when blueprints are created dynamically in code.
- Removed `.grep()` calls and improved performance of config directory traversing.