[neon-notifications] Dev Required: qt6-mqtt - 6.12.0-beta2

[Neon CI]

https://build.neon.kde.org/job/watcher_release_qt6_qt6-mqtt/621/display/redirect

#<Debian::UScan::DEHS::Package:0x0000717db8ca40c0 @name="qt6-mqtt", @debian_uversion="6.11.1", @debian_mangled_uversion="6.11.1", @upstream_version="6.12.0-beta2", @upstream_url="https://github.com/qt/qtmqtt/archive/refs/tags/v6.12.0-beta2.tar.gz", @status="Newer version available">