CI: cirrus: update FreeBSD image to 12.2

we already tried to run FreeBSD-stable. it is pain,
so we use FreeBSD releases, we need to keep packages and release in sync.

let us update to released FreeBSD-12.2
diff --git a/.cirrus.yml b/.cirrus.yml
index e8b70de..0ac21bf 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -1,7 +1,7 @@
 FreeBSD_task:
   freebsd_instance:
     matrix:
-      image_family: freebsd-12-1
+      image_family: freebsd-12-2
   only_if: $CIRRUS_BRANCH =~ 'master|next'
   install_script:
     - pkg update -f && pkg upgrade -y && pkg install -y openssl git gmake lua53 socat