Update adguard.sh

default Debian 12
fixes https://github.com/tteck/Proxmox/issues/1538

ct/adguard.sh

@@ -24,7 +24,7 @@ var_disk="2"
 var_cpu="1"
 var_ram="512"
 var_os="debian"
-var_version="11"
+var_version="12"
 variables
 color
 catch_errors