updated project style guidelines

lib/model/holidays/holidaysProps.dart

@@ -10,9 +10,7 @@ class HolidaysProps extends DataHolder {
   GetHolidaysResponse get getHolidaysResponse => _getHolidaysResponse!;
 
   @override
-  List<ApiResponse?> properties() {
-    return [_getHolidaysResponse];
-  }
+  List<ApiResponse?> properties() => [_getHolidaysResponse];
 
   @override
   void run() {
@@ -23,4 +21,4 @@ class HolidaysProps extends DataHolder {
       },
     );
   }
-}
+}