Auto merge of #120869 - devnexen:update_fbsd_ci, r=Mark-Simulacrum

ci update freebsd version proposal, freebsd 12 being eol

raising to the lowest still active supported freebsd version.
From 13.1 (already eol too), freebsd introduces a cpu affinity layer
with linux. It also introduces a api compatible copy_file_range which
can be used like its linux's counterpart.
The former is essential to build rust-lang/rust#120589, therefore breaks the backward
compatibility with the previous FreeBSD releases.

Blocked on rust-lang/rust#130465

Author: bors