[neon-notifications] Dev Required: qxmpp - 1.4.0

[Neon CI]

https://build.neon.kde.org/job/watcher_release_backports-focal_qxmpp/103/display/redirect

#<Debian::UScan::DEHS::Package:0x0000558b001a0500 @name="qxmpp", @debian_uversion="1.3.2", @debian_mangled_uversion="1.3.2", @upstream_version="1.4.0", @upstream_url="https://github.com/qxmpp-project/qxmpp/archive/v1.4.0.tar.gz", @status="Newer version available">