TypeError gulp-webp-css when adding img class or data attribute?

Question

JavaScript

Gulp complains when adding a class or data attribute that specifies a color. How to fix this error?

<div class="product-prev__header">
    <div class="js-product-prev__slider">
      <img class="product-prev__img" src="img/content/products/product-1/8521-B.jpg" alt="Самокат Smiley Mini 8521 (синий)"
        data-color="#1089ff">
      <img class="product-prev__img" src="img/content/products/product-1/8521-R.jpg" alt="Самокат Smiley Mini 8521 (красный)"
        data-color="#f00">
      <img class="product-prev__img" src=" img/content/products/product-1/8521-O.jpg" alt="Самокат Smiley Mini 8521 (оранжевый)"
        data-color="#de5216">
    </div>
  </div>