[neon-notifications] kdenlive new version 18.12.0

[Neon CI]

https://build.neon.kde.org/job/watcher_release_forks_kdenlive/276/display/redirect

#<Debian::UScan::DEHS::Package:0x00007ff468006c98 @name="kdenlive", @debian_uversion="18.08.3", @debian_mangled_uversion="18.08.3", @upstream_version="18.12.0", @upstream_url="http://download.kde.internal.neon.kde.org/stable/applications/18.12.0/src/kdenlive-18.12.0.tar.xz", @status="Newer version available">