title: vue-google-chart how to change colour when filter click selected?
body: <p>I have created stack column chart with filter when i click stack column.</p>
  <p>But when i click selected, <code>color</code> is change to default <code>color</code> (blue)</p>
  <p>Here my vue app</p>
  <p><a href="https://codesandbox.io/s/vue-dashboard-chart-6lvx4?file=/src/components/Dashboard.vue" rel="nofollow noreferrer">https://codesandbox.io/s/vue-dashboard-chart-6lvx4?file=/src/components/Dashboard.vue</a></p>
  <p><strong>I've expected color selected same of color in stack column.</strong></p>
  <p>How is it done using <code>Vue-google-charts</code>?</p>
  <p>Thanks an best regards, Dede</p>