Support Debian Trixie when package becomes available

[jsf9k]

Debian Trixie did have the [freeipa-client] package available but it was pulled because of an issue in the sssd package (which was also pulled). Please see:

• https://tracker.debian.org/news/1521964/freeipa-removed-from-testing/
• https://tracker.debian.org/news/1522104/sssd-removed-from-testing/
• https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1068063

Originally posted by @mcdonnnj in #47 (comment)