TYPO3 11: Error Class 'GridElementsTeam\Gridelements\Xclass\WorkspaceRestriction' not found

After fixing #205 this error is thrown:

Error Class 'GridElementsTeam\Gridelements\Xclass\WorkspaceRestriction' not found

how to fix: add use TYPO3\CMS\Core\Database\Query\Restriction\WorkspaceRestriction; above the class.