Roll Observatory packages and add a roll script

packages/charted/lib/charts/src/chart_config_impl.dart

 //
 // Copyright 2014 Google Inc. All rights reserved.
 //
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 //
 
 part of charted.charts;
 
@@ skipping 115 matching lines @@
   set isRTL(bool value) {
     if (_isRTL != value && value != null) {
       _isRTL = value;
       notifyChange(const ChartConfigChangeRecord());
     }
   }
 
   @override
   bool get isRTL => _isRTL;
 }