Cirrus CI: Bump FreeBSD image from 13.3 to 13.4 (#4841)

Author: kinke

.cirrus.yml

@@ -206,9 +206,9 @@ task:
   << : *COMMON_STEPS_TEMPLATE
 
 task:
-  name: FreeBSD 13.3 x64
+  name: FreeBSD 13.4 x64
   freebsd_instance:
-    image_family: freebsd-13-3
+    image_family: freebsd-13-4
     cpu: 4
     memory: 8G
   timeout_in: 60m