Commandfiles are now encouraged to inject their dependencies via Autowire (#5893). The drush.services.yml file is deprecated and may be removed in Drush 13. Now is also a good time to update commandfiles to use PHP Attributes instead of annotations.
A new content authoring command: entity:create. Added in 12.4.4 and so fun we had to mention it again in this minor release.
Full Changelog: 12.4.4...12.5.0