CFT: traefik3 is coming in Q4

Hey users of traefik,

In about four weeks from now, after the quarterly branch has been cut,
I plan to bump traefik to the new major 3.x branch.

Unlike the previous migration from 1.x to 2.x, there is no major config
format overhaul this time, i.e. many configuration will just work out
of the box or require only small updates. The details are available at:
https://doc.traefik.io/traefik/migration/v2-to-v3/

Because of this gentle migration, I don't plan having two traefik ports
in the tree at the same time. Instead, latest will move to traefik3 in
October 2024, and the quarterly branch in January 2025.

If you want to test your configs and prepare for the change, I have a
patch to update a local ports tree to 3.x in this tracking bug:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=281329

Feel free to try it out, and add comments to the bug if you identify
any major issues.

Best regards
Riggs