feat: update ZingChart version to v2.9.0 and to use the ES6 module version of the library

Author: Nick Ardecky

ZingChart.vue

@@ -4,7 +4,7 @@
 
 <script>
 // Import the zingchart library to be used globally.
-import 'zingchart';
+import zingchart from 'zingchart/es6';
 import constants from 'zingchart-constants';
 const { DEFAULT_WIDTH, DEFAULT_HEIGHT, DEFAULT_OUTPUT, EVENT_NAMES, METHOD_NAMES } = constants;