Make libffi version more flexible (inventree#7734)

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

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

Author: matmair

.pkgr.yml

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

contrib/install.sh

@@ -75,6 +75,7 @@ root_command() {
           ;;
       "Debian GNU/Linux" | "debian gnu/linux" | Raspbian)
           if [[ $VER == "12" ]]; then
+              DIST_VER="11"
               SUPPORTED=true
           elif [[ $VER == "11" ]]; then
               SUPPORTED=true