message: Implemented hide when scrolling prop
  Doesn't seem to work properly because starts off hidden?! Is this current bug?
diff: @@ -71,6 +71,8 @@ using namespace facebook::react;
  if (@available(iOS 13.0, *)) {
  [self.searchController.searchBar.searchTextField setBackgroundColor:RCTUIColorFromSharedColor(newViewProps.barTintColor)];
  }
  + _hideWhenScrolling = newViewProps.hideWhenScrolling;
  + [self.reactViewController.navigationItem setHidesSearchBarWhenScrolling:_hideWhenScrolling];
  [super updateProps:props oldProps:oldProps];
  }
  