Fix warning.

test/plugs/legacy_authentication_plug_test.exs

@@ -45,7 +45,7 @@ test "it authenticates the auth_user if present and password is correct and rese
     conn =
       with_mock User,
         reset_password: fn user, %{password: password, password_confirmation: password} ->
-          send(self, :reset_password)
+          send(self(), :reset_password)
           {:ok, user}
         end do
         conn