Issue #3098707 by blazey: Add purgeDeletedWorkspacesBatch to the WorkspaceManagerInterface

(cherry picked from commit a8d43caa)

core/modules/workspaces/src/WorkspaceManagerInterface.php

@@ -100,4 +100,9 @@ public function executeOutsideWorkspace(callable $function);
    */
   public function shouldAlterOperations(EntityTypeInterface $entity_type);
 
+  /**
+   * Deletes the revisions associated with deleted workspaces.
+   */
+  public function purgeDeletedWorkspacesBatch();
+
 }