Merge branch 'winh-issue-boards-service-ee-refactoring-note' into 'master'

Add note about refactoring to EE-specific board_service.js

See merge request gitlab-org/gitlab-ee!14993

ee/app/assets/javascripts/boards/services/board_service.js

+/**
+ * This file is intended to be deleted.
+ * The existing functions will removed one by one in favor of using the board store directly.
+ * see https://gitlab.com/gitlab-org/gitlab-ce/issues/61621
+ */
+
 import BoardService from '~/boards/services/board_service';
 import boardsStore from '~/boards/stores/boards_store';