provide logo at feed.atom (debug)

lib/pleroma/web/ostatus/feed_representer.ex

@@ -27,7 +27,7 @@ def to_simple_form(user, activities, _users) do
         {:id, h.(OStatus.feed_path(user))},
         {:title, ['#{user.nickname}\'s timeline']},
         {:updated, h.(most_recent_update)},
-        {:logo, (User.avatar_url(user) |> MediaProxy.url())},
+        {:logo, [to_charlist(User.avatar_url(user) |> MediaProxy.url())]},
         {:link, [rel: 'hub', href: h.(OStatus.pubsub_path(user))], []},
         {:link, [rel: 'salmon', href: h.(OStatus.salmon_path(user))], []},
         {:link, [rel: 'self', href: h.(OStatus.feed_path(user)), type: 'application/atom+xml'], []},