[neon-notifications] Dev Required: assimp - 5.1.6

[Neon CI]

https://build.neon.kde.org/job/watcher_release_backports-focal_assimp/38/display/redirect

#<Debian::UScan::DEHS::Package:0x000056409b0d1a10 @name="assimp", @debian_uversion="5.1.3~ds0", @debian_mangled_uversion="5.1.3", @upstream_version="5.1.6", @upstream_url="https://github.com/assimp/assimp/archive/refs/tags/v5.1.6.tar.gz", @status="Newer version available">