[neon-notifications] kdenlive new version 18.12.3

[Neon CI]

https://build.neon.kde.org/job/watcher_release_forks_kdenlive/363/display/redirect

#<Debian::UScan::DEHS::Package:0x000055b01fa2a510 @name="kdenlive", @debian_uversion="18.12.2", @debian_mangled_uversion="18.12.2", @upstream_version="18.12.3", @upstream_url="http://download.kde.internal.neon.kde.org/stable/applications/18.12.3/src/kdenlive-18.12.3.tar.xz", @status="Newer version available">