Add Entry ID to available fields for Zapier

<?php
// Add the entry ID as an available field for Zapier
// This will add the entry ID to field 4 in form 16 - edit these values to match your form.
add_filter( 'gform_zapier_field_value', 'add_entry_id_zapier', 10, 4 );
function add_entry_id_zapier( $field_value, $form_id, $field_id, $entry ){
    // apply to field 4 in form 16 only
    if ( $form_id == 16 && $field_id == 4 ){
        return $entry['id'];
    }
    else {
        return $field_value;
    }
}