update method
Implementation
void update(NeumorphicThemeUpdater themeUpdater) {
final update = themeUpdater(value.current);
if (value.useDark) {
final newValue = value.copyWith(darkTheme: update);
//this.value = newValue;
this.onChanged(newValue);
} else {
final newValue = value.copyWith(theme: update);
//this.value = newValue;
this.onChanged(newValue);
}
}