[Credo] Fix the warnings

.gitlab-ci.yml

@@ -42,4 +42,4 @@ unit-testing:
 analysis:
   stage: analysis
   script:
-    - mix credo list
+    - mix credo list --only=warnings

lib/pleroma/web/federator/federator.ex

@@ -24,7 +24,7 @@ defmodule Pleroma.Web.Federator do
 
   def init() do
     # 1 minute
-    Process.sleep(1000 * 60 * 1)
+    Process.sleep(1000 * 60)
     refresh_subscriptions()
   end
 

test/web/twitter_api/twitter_api_controller_test.exs

@@ -490,7 +490,7 @@ test "does not show DMs in mentions timeline", %{conn: conn, user: current_user}
 
       response = json_response(conn, 200)
 
-      assert length(response) == 0
+      assert Enum.empty?(response)
     end
   end