[neon-notifications] Dev Required: assimp - 5.1.5

[Neon CI]

https://build.neon.kde.org/job/watcher_release_backports-focal_assimp/18/display/redirect

#<Debian::UScan::DEHS::Package:0x0000558e1db396c8 @name="assimp", @debian_uversion="5.1.3~ds0", @debian_mangled_uversion="5.1.3", @upstream_version="5.1.5", @upstream_url="https://github.com/assimp/assimp/archive/refs/tags/v5.1.5.tar.gz", @status="Newer version available">