.some-class {
  font-size: 5em;
  color: #f35626; /* This is not needed because you are using -webkit-text-fill-color: transparent.
                      but It can be usefull with the currentColor property */
  -webkit-background-clip: text;
  -moz-background-clip: text;
  -ms-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  -moz-text-fill-color: transparent;
  -ms-text-fill-color: transparent;
  text-fill-color: transparent;
  background-image: -webkit-linear-gradient(92deg, currentColor, #feab3a);
  background-image:  -moz-linear-gradient(92deg, currentColor, #feab3a);
  background-image:  -ms-linear-gradient(92deg, currentColor, #feab3a);
  background-image:  linear-gradient(92deg, currentColor, #feab3a);
  animation: hue 60s infinite linear
}

@-webkit-keyframes hue {
  0%{
    -webkit-filter: hue-rotate(0deg)
  }
  100%{
    -webkit-filter: hue-rotate(-360deg)
  }
}
@-moz-keyframes hue {
  0%{
    -moz-filter: hue-rotate(0deg)
  }
  100%{
    -moz-filter: hue-rotate(-360deg)
  }
}
@-ms-keyframes hue {
  0%{
    -ms-filter: hue-rotate(0deg)
  }
  100%{
    -ms-filter: hue-rotate(-360deg)
  }
}
@keyframes hue {
  0%{
    filter: hue-rotate(0deg)
  }
  100%{
    filter: hue-rotate(-360deg)
  }
}