function interpolateRGB(
  startColor,
  endColor,
  t = 0.5,
  exportFormat = "hex"
) {
  var obj = interpolateRGBObject(startColor, endColor, t);

  return format(obj, exportFormat);
}
@deprecated

instead of this,  use blend function

@param {*} startColor
@param {*} endColor
@param {*} t