[#10951] Create a cron job to warn user with a old brouillon

app/jobs/cron/notify_old_brouillon_dossiers_soon_deleted_job.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+class Cron::NotifyOldBrouillonDossiersSoonDeletedJob < Cron::CronJob
+  self.schedule_expression = "every day at 9:00"
+
+  def perform
+    Dossier
+      .state_brouillon
+      .where(updated_at: ..3.months.ago)
+      .where("notified_soon_deleted_sent_at IS NULL OR notified_soon_deleted_sent_at < updated_at")
+      .find_each do |dossier|
+        DossierMailer.notify_old_brouillon_soon_deleted(dossier).deliver_later
+        dossier.update_column(:notified_soon_deleted_sent_at, Time.zone.now)
+      end
+  end
+end