Fix redirect handling not working with HTTPoison

lib/frenzy/network.ex

@@ -12,9 +12,9 @@ defmodule Frenzy.Network do
       {:ok, %HTTPoison.Response{status_code: status_code, headers: headers}}
       when status_code in @http_redirect_codes ->
         headers
-        |> Enum.find(fn {name, _value} -> name == "location" end)
+        |> Enum.find(fn {name, _value} -> String.downcase(name) == "location" end)
         |> case do
-          {"location", new_url} ->
+          {_, new_url} ->
             new_url =
               case URI.parse(new_url) do
                 %URI{host: nil, path: path} ->