Input-Group appended icon is not triggering picker (BS4)

[social-butterfly]

Expected behaviour

Open calendar picker when clicking on the input-group appended icon.

Actual behaviour

Input group appended icon does NOT trigger opening of calendar.

Datepicker version used

v1.9.0

Also used

Bootstrap 4.2.1, jQuery 3.3.1, FontAwesome 5 (free)

Example code

<div class="input-group date">
    <input type="text" class="form-control form-control-sm" id="joined" name="joined" value="">
    <div class="input-group-append">
        <span class="input-group-text"><i class="fas fa-calendar-alt"></i></span>
    </div>
</div>

<script>
$('#joined').datepicker({
                format: "dd/mm/yyyy",
                weekStart: 1,
                maxViewMode: 3,
                endDate: "0d",
                todayBtn: "linked",
                language: "en-NZ"
            });
</script>