fixes "invalid form body" from webhook

discord doesn't let "discord" exist in webhooks anymore. end all.
I may have to add a special rule to have the bot post a message
instead of a webhook service if someone has "discord" in their
nick.

lib/webhookservice.ex

@@ -31,8 +31,8 @@ defmodule Discordirc.WebhookService do
 
       case DiscordAPI.create_webhook(
              channel_id,
-             %{name: "discordirc hook", avatar: avatar},
-             "discordirc proxy hook"
+             %{name: "irc relay hook", avatar: avatar},
+             "irc relay hook"
            ) do
         {:ok, hook} ->
           case state.hooks do