Fix MoveActivityExpirationsToOban migration

This never would have worked correctly.

warning: Pleroma.Workers.PurgeExpiredActivity.enqueue/1 is undefined or private. Did you mean:

      * enqueue/2

priv/repo/migrations/20200825061316_move_activity_expirations_to_oban.exs

@@ -23,10 +23,12 @@ defmodule Pleroma.Repo.Migrations.MoveActivityExpirationsToOban do
     |> Pleroma.Repo.stream()
     |> Stream.each(fn expiration ->
       with {:ok, expires_at} <- DateTime.from_naive(expiration.scheduled_at, "Etc/UTC") do
-        Pleroma.Workers.PurgeExpiredActivity.enqueue(%{
-          activity_id: FlakeId.to_string(expiration.activity_id),
-          expires_at: expires_at
-        })
+        Pleroma.Workers.PurgeExpiredActivity.enqueue(
+          %{
+            activity_id: FlakeId.to_string(expiration.activity_id)
+          },
+          scheduled_at: expires_at
+        )
       end
     end)
     |> Stream.run()