fix: event should be fired from the element the date picker is attached to

[mfazekas]

Instead of

    window.addEventListener('apply.daterangepicker', function (ev) {
        console.log(ev.detail.startDate.format('YYYY-MM-DD'));
        console.log(ev.detail.endDate.format('YYYY-MM-DD'));
    });

We should be able to write:

   new DateRangePicker(element...)

   
    element.addEventListener('apply.daterangepicker', function (ev) {
        console.log(ev.detail.startDate.format('YYYY-MM-DD'));
        console.log(ev.detail.endDate.format('YYYY-MM-DD'));
    });