Add return type to PowerSyncDatbase connect

Author: thedalelakes

packages/powersync/lib/src/powersync_database.dart

@@ -155,7 +155,7 @@ class PowerSyncDatabase with SqliteQueries implements SqliteConnection {
   /// The connection is automatically re-opened if it fails for any reason.
   ///
   /// Status changes are reported on [statusStream].
-  connect({required PowerSyncBackendConnector connector}) async {
+  Future<void> connect({required PowerSyncBackendConnector connector}) async {
     await initialize();
 
     // Disconnect if connected