title: How to animate gradient?
body: <p>How to animate gradient from color#1 to color#2? Something similar to</p>
  <p><a href="https://i.stack.imgur.com/9JyII.gif" rel="noreferrer"><img src="https://i.stack.imgur.com/9JyII.gif" alt="enter image description here" /></a></p>
  <p>I'm planning to use it as health-bar for unit (so, it will be finit animation starting with green and ending with red)</p>