ci: update FreeBSD image to currently supported 13.2 release

FreeBSD 12.x is now EOL.

Signed-off-by: Ed Maste <emaste@FreeBSD.org>

.cirrus.yml

@@ -1,15 +1,15 @@
 env:
   CIRRUS_CLONE_DEPTH: 1
 
-freebsd_12_task:
+freebsd_13_task:
   env:
     GIT_PROVE_OPTS: "--timer --jobs 10"
     GIT_TEST_OPTS: "--no-chain-lint --no-bin-wrappers"
     MAKEFLAGS: "-j4"
     DEFAULT_TEST_TARGET: prove
     DEVELOPER: 1
   freebsd_instance:
-    image_family: freebsd-12-3
+    image_family: freebsd-13-2
     memory: 2G
   install_script:
     pkg install -y gettext gmake perl5