Nextcloud: update version to 29 #66

Job	Run time
Build App Containers (etherpad) / Build etherpad	42s
Build App Containers (limesurvey) / Build limesurvey	40s
Build App Containers (indico) / Build indico	2m 35s
Build App Containers (minecraft) / Build minecraft	17s
Build App Containers (nextcloud) / Build nextcloud	1m 38s
Build App Containers (sogo) / Build sogo	3m 10s
	9m 2s

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