Change 'name' to 'instance_name' so option is used when running non-interactive

lib/mix/tasks/pleroma/instance.ex

@@ -75,7 +75,7 @@ defmodule Mix.Tasks.Pleroma.Instance do
       name =
         Common.get_option(
           options,
-          :name,
+          :instance_name,
           "What is the name of your instance? (e.g. Pleroma/Soykaf)"
         )