Autoload: drulma/src/Render/Callback.php does not comply with psr-4 autoloading standard

Problem/Motivation

When I run composer dump-autoload, Drulma has an issue:

Class Drupal\drulma\Render\Callback located in ./web/themes/contrib/drulma/src/Render/Callback.php does not comply with psr-4 autoloading standard (rule: Drulma\ => ./web/themes/contrib/drulma/src). Skipping.