ci: Update cirrus' freebsd image to 14.1

This should fix CI which is failing lately like this:
https://cirrus-ci.com/task/4665005218463744

ld-elf.so.1: /lib/libc.so.7: version FBSD_1.8 required by
/usr/local/bin/stack not found

.cirrus.yml

@@ -1,5 +1,5 @@
 freebsd_instance:
-  image_family: freebsd-14-0
+  image_family: freebsd-14-1
 
 build_task:
   # Don't change this name without adjusting .github/workflows/build.yaml