close CacheStore in CacheManager.dispose and cancel internal timer

Author: EdwynZN

flutter_cache_manager/lib/src/cache_manager.dart

@@ -291,6 +291,6 @@ class CacheManager implements BaseCacheManager {
   /// Closes the cache database
   @override
   Future<void> dispose() async {
-    await _config.repo.close();
+    await _store.close();
   }
 }

flutter_cache_manager/lib/src/cache_store.dart

@@ -199,6 +199,7 @@ class CacheStore {
   }
 
   Future<void> dispose() async {
+    _scheduledCleanup?.cancel();
     final provider = await _cacheInfoRepository;
     await provider.close();
   }