Update FreeBSD CI images

* FreeBSD 12 is EoL.  Drop it.
* Use the latest FreeBSD 13 and 14 versions.
* Add FreeBSD 15.0-CURRENT.
* Use the current python version.

Sponsored by:	ConnectWise
Reviewed-by: Alexander Motin <[email protected]>
Signed-off-by:	Alan Somers <[email protected]>
Closes openzfs#17139

Author: asomers

.cirrus.yml

@@ -5,16 +5,16 @@ env:
 build_task:
   matrix:
     freebsd_instance:
-      image_family: freebsd-12-4
+      image_family: freebsd-13-5
     freebsd_instance:
-      image_family: freebsd-13-2
+      image_family: freebsd-14-2
     freebsd_instance:
-      image_family: freebsd-14-0-snap
+      image_family: freebsd-15-0-snap
   prepare_script:
-    - pkg install -y autoconf automake libtool gettext-runtime gmake ksh93 py39-packaging py39-cffi py39-sysctl
+    - pkg install -y autoconf automake libtool gettext-runtime gmake ksh93 py311-packaging py311-cffi py311-sysctl
   configure_script:
     - env MAKE=gmake ./autogen.sh
-    - env MAKE=gmake ./configure --with-config="user" --with-python=3.9
+    - env MAKE=gmake ./configure --with-config="user" --with-python=3.11
   build_script:
     - gmake -j `sysctl -n kern.smp.cpus`
   install_script: