polyfill for IE?

Hey Vrata,

I’ve had some issues with business some users still stuck using IE11 (and possibly earlier versions) not being able to enter data in cloned rows due to IE not supporting endsWith().
I’ve had to add this polyfill to cf7-grid-layout-public.js prior to line commented ‘//add input name as class to parent span’.

//https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith
if (!String.prototype.endsWith) {
  String.prototype.endsWith = function(searchString, position) {
      var subjectString = this.toString();
      if (typeof position !== 'number' || !isFinite(position) || Math.floor(position) !== position || position > subjectString.length) {
        position = subjectString.length;
      }
      position -= searchString.length;
      var lastIndex = subjectString.indexOf(searchString, position);
      return lastIndex !== -1 && lastIndex === position;
  };
}

Is there any chance this could be added in future releases?