Helper/IRIS: fex error message encoding (use utf8)

lib/Travelynx/Helper/IRIS.pm

 package Travelynx::Helper::IRIS;
+
 # Copyright (C) 2020 Daniel Friesel
 #
 # SPDX-License-Identifier: MIT
@@ -7,6 +8,8 @@ use strict;
 use warnings;
 use 5.020;
 
+use utf8;
+
 use Travel::Status::DE::IRIS;
 
 sub new {