Merge branch 'renovate/templates-nextcloud-28.x' into 'master'

Update nextcloud Docker tag to v28

See merge request !104

verwaltung/docker_nextcloud/templates/docker-compose.yml

@@ -27,7 +27,7 @@ services:
 
   app:
 
-    image: nextcloud:27.1.3-apache
+    image: nextcloud:28.0.1-apache
     restart: always
     volumes:
       - /srv/nextcloud/data/:/var/www/html/