Fix Sidekiq warning when pushing DMs to direct timeline

app/services/fan_out_on_write_service.rb

@@ -92,7 +92,7 @@ class FanOutOnWriteService < BaseService
 
   def deliver_to_direct_timelines!
     FeedInsertWorker.push_bulk(@status.mentions.includes(:account).map(&:account).select { |mentioned_account| mentioned_account.local? }) do |account|
-      [@status.id, account.id, :direct, update: update?]
+      [@status.id, account.id, 'direct', { 'update' => update? }]
     end
   end