[neon-notifications] Releasing: kdegraphics-thumbnailers - 21.08.2

[Neon CI]

https://build.neon.kde.org/job/watcher_release_kde_kdegraphics-thumbnailers/17/display/redirect

#<Debian::UScan::DEHS::Package:0x000055ca1d4e7bd0 @name="kdegraphics-thumbnailers", @debian_uversion="21.08.1", @debian_mangled_uversion="21.08.1", @upstream_version="21.08.2", @upstream_url="http://download.kde.internal.neon.kde.org/stable/release-service/21.08.2/src/kdegraphics-thumbnailers-21.08.2.tar.xz", @status="Newer version available">