chore(examples): Update reactive prop examples

src/examples/ReactivePropExample.js

@@ -4,8 +4,14 @@ import reactiveProp from '../mixins/reactiveProp'
 export default {
   extends: Bar,
   mixins: [reactiveProp],
+  data: () => ({
+    options: {
+      responsive: true,
+      maintainAspectRatio: false
+    }
+  }),
 
   mounted () {
-    this.renderChart(this.chartData, {responsive: true, maintainAspectRatio: false})
+    this.renderChart(this.chartData, this.options)
   }
 }