feat: center app bar title

lib/main.dart

@@ -15,7 +15,7 @@ class TheApp extends StatelessWidget {
         appBar: AppBar(
           backgroundColor: Colors.deepPurple,
           title: const Text("Tamagochi 2.0"),
-          titleSpacing: Align(this.title),  // I want to center-align title horizontaly; ai!
+          centerTitle: true,
         ),
         body: Container(
           child: const Text("this is a body"),