[neon-notifications] Releasing: agenda - 0.5.1

[Neon CI]

https://build.neon.kde.org/job/watcher_release_neon-packaging_agenda/89/display/redirect

#<Debian::UScan::DEHS::Package:0x0000556324b6c088 @name="agenda", @debian_uversion="0.5.0", @debian_mangled_uversion="0.5.0", @upstream_version="0.5.1", @upstream_url="http://download.kde.internal.neon.kde.org/stable/maui/agenda/0.5.1/agenda-0.5.1.tar.xz", @status="Newer version available">