title: Animating a button that fills up with a color
body: <p>In need to create an animation. the animation is a color that fills a button according to the percentage that is given.
  that's how is should look:
  <img src="https://i.stack.imgur.com/pQQ7W.png" alt="enter image description here"></p>
  
  <p>As you see, the yellow color is filling up 44% of the button.
  How can I do this with animation so that it starts "empty" and ends like the image I uploaded?
  Thanks!</p>