title: Changing colors of icons in tree node
body: <p>As you can see in my stackblitz demo, I implemented a tree with checkboxes. Now, I want to change the colors of circles for every node. For example, I want to make the circle red for Documents, black for Pictures and yellow for Movies. How can I do this?</p>
  <p><a href="https://stackblitz.com/edit/primeng-treeselection-demo-ozpvr2?file=src/app/app.component.html" rel="nofollow noreferrer">https://stackblitz.com/edit/primeng-treeselection-demo-ozpvr2?file=src/app/app.component.html</a></p>