v0.2.8 - bugfix release

Fixed

• superset_dataset_update silently reset always_filter_main_dttm to false. Superset's PUT /dataset/{id} drops the flag whenever it is omitted from the payload, so updating a dataset's columns (e.g. to set Russian verbose_name labels) turned off the main datetime filter and broke time filtering on every dependent dashboard. The tool now preserves the current value automatically when columns are replaced, and exposes a new optional always_filter_main_dttm parameter to set it explicitly.

Full Changelog: v0.2.7...v0.2.8