Scale up lists to CPX11

Archiving arch-commits mails maxes out the single vCPU of CX11 and
results in High CPU Prometheus alert. If we decide not to maintain
mail archive for arch-commits, then we can likely scale back down.

tf-stage1/archlinux.tf

@@ -80,7 +80,7 @@ locals {
       domain      = "homedir"
     }
     "lists.archlinux.org" = {
-      server_type = "cx11"
+      server_type = "cpx11"
       domain      = "lists"
     }
     "mail.archlinux.org" = {