tests: remove comma for PHP 7.1 7.2 compatibility

Author: phil-davis

tests/VObject/ITip/BrokerAttendeeReplyTest.php

@@ -1255,7 +1255,7 @@ public function testNewEventWithReply(): void
 ATTENDEE;PARTSTAT=ACCEPTED;CN=One:mailto:one@example.org
 END:VEVENT
 END:VCALENDAR
-ICS,
+ICS
             ],
         ];