testing: geoserver 2.27.3 & 2.28.0

[Landry Breuil]

Hello,

a bunch of geoserver releases were made last week, cf:
https://geoserver.org/announcements/vulnerability/2025/10/21/geoserver-2-27-3-released.html
https://geoserver.org/announcements/vulnerability/2025/10/14/geoserver-2-28-0-released.html

both contain security fixes, so would be a good idea to update. I've
prepared those in
https://github.com/georchestra/georchestra/issues/4594, light runtime
testing with tomcat 9 showed they were okay but i haven't "extensively"
tested them in various exotic configurations.

versioned wars are available at
https://packages.georchestra.org/bot/wars/master/ for the ones who want
to play with it. https://demo.georchestra.org/geoserver/ has been
updated to use 2.28.0.

--
Landry Breuil