[neon-notifications] Dev Required: fastfloat - 6.0.0

[Neon CI]

https://build.neon.kde.org/job/watcher_release_neon-packaging_fastfloat/292/display/redirect

#<Debian::UScan::DEHS::Package:0x000055ebca94aed8 @name="fastfloat", @debian_uversion="4.0.0", @debian_mangled_uversion="4.0.0", @upstream_version="6.0.0", @upstream_url="https://github.com/fastfloat/fast_float/archive/refs/tags/v6.0.0.tar.gz", @status="Newer version available">