Update Application.php

[ReneFloitgraf]

trafficstars

Should help make the app compatible to nextcloud 28...

Old: $eventDispatcher = $context->getServerContainer()->getEventDispatcher();

New: $eventDispatcher = $this->getContainer()->query(IEventDispatcher::class);

And addListener updated. See: https://docs.nextcloud.com/server/stable/developer_manual/basics/events.html

Seems to work. Please correct, if I am wrong.