Make libffi version more flexible (#7734)

* Make libffi version more flexible
Can not install on debian 12
Fixes #6036

* target v11 packaging on v12 install
we are only targeting one version per debian / ubuntu channel. This should not present a problem

.pkgr.yml

@@ -35,7 +35,7 @@ dependencies:
   - gettext
   - nginx
   - jq
-  - libffi7
+  - "libffi7 | libffi8"
 targets:
   ubuntu-20.04: true
   debian-11: true