[neon-notifications] Dev Required: sip6 - 6.15.3

[Neon CI]

https://build.neon.kde.org/job/watcher_release_forks_sip6/536/display/redirect

#<Debian::UScan::DEHS::Package:0x0000749cb65db598 @name="sip6", @debian_uversion="6.14.0", @debian_mangled_uversion="6.14.0", @upstream_version="6.15.3", @upstream_url="https://github.com/Python-SIP/sip/archive/refs/tags/6.15.3.tar.gz", @status="Newer version available">