[neon-notifications] Releasing: yakuake - 21.04.0

[Neon CI]

https://build.neon.kde.org/job/watcher_release_kde_yakuake/465/display/redirect

#<Debian::UScan::DEHS::Package:0x000055fd07e19ad8 @name="yakuake", @debian_uversion="20.12.3", @debian_mangled_uversion="20.12.3", @upstream_version="21.04.0", @upstream_url="https://download.kde.internal.neon.kde.org/stable/release-service/21.04.0/src/yakuake-21.04.0.tar.xz", @status="Newer version available">