Based on the Debian Wiki, plans have since changed[0] (unless this page is outdated?). That LWN article is from June, the wiki article was last edited in September.

My understanding from the mailing list is that they're planning on using GitLab, at least that's what I heard last. I could always be wrong.

[0]: https://wiki.debian.org/Alioth#Deprecation_of_Alioth