feat(y-indexeddb): cleanup (#2207)

Co-authored-by: himself65 <himself65@outlook.com>

packages/y-indexeddb/src/shared.ts

@@ -11,7 +11,7 @@ export function upgradeDB(db: IDBPDatabase<BlockSuiteBinaryDB>) {
 export interface IndexedDBProvider {
   connect: () => void;
   disconnect: () => void;
-  cleanup: () => void;
+  cleanup: () => Promise<void>;
   whenSynced: Promise<void>;
 }