don't expire pinned posts

lib/mix/tasks/pleroma/database.ex

@@ -150,8 +150,12 @@ def run(["ensure_expiration"]) do
     |> Pleroma.RepoStreamer.chunk_stream(100)
     |> Stream.each(fn activities ->
       Enum.each(activities, fn activity ->
+        user = User.get_cached_by_ap_id(activity.actor)
+
+        if activity.id not in user.pinned_activities do
           expires_at = Timex.shift(activity.inserted_at, days: days)
           Pleroma.ActivityExpiration.create(activity, expires_at, false)
+        end
       end)
     end)
     |> Stream.run()