feat(dunning): schedule process dunning campaigns jobs every hour at 45'

 ## Roadmap Task

👉 https://getlago.canny.io/feature-requests/p/set-up-payment-retry-logic
👉
https://getlago.canny.io/feature-requests/p/send-reminders-for-overdue-invoices

 ## Context

We want to automate dunning process so that our users don't have to look
at each customer to maximize their chances of being paid retrying
payments of overdue balances and sending email reminders.

We're first automating the overdue balance payment request, before
looking at individual invoices.

 ## Description

This change adds the scheduler to run the ProcessDunningCampaigns job
every hour at 45 minute.

clock.rb

@@ -122,4 +122,10 @@ module Clockwork
       .set(sentry: {"slug" => 'lago_compute_daily_usage', "cron" => '15 */1 * * *'})
       .perform_later
   end
+
+  every(1.hour, "schedule:process_dunning_campaigns", at: "*:45") do
+    Clock::ProcessDunningCampaignsJob
+      .set(sentry: {"slug" => "lago_process_dunning_campaigns", "cron" => "45 */1 * * *"})
+      .perform_later
+  end
 end

spec/clockwork_spec.rb

@@ -135,4 +135,25 @@
       expect(Clock::ComputeAllDailyUsagesJob).to have_been_enqueued
     end
   end
+
+  describe "schedule:process_dunning_campaigns" do
+    let(:job) { "schedule:process_dunning_campaigns" }
+    let(:start_time) { Time.zone.parse("1 Apr 2022 00:01:00") }
+    let(:end_time) { Time.zone.parse("1 Apr 2022 01:01:00") }
+
+    it "enqueue a process dunning campaigns job" do
+      Clockwork::Test.run(
+        file: clock_file,
+        start_time:,
+        end_time:,
+        tick_speed: 1.second
+      )
+
+      expect(Clockwork::Test).to be_ran_job(job)
+      expect(Clockwork::Test.times_run(job)).to eq(1)
+
+      Clockwork::Test.block_for(job).call
+      expect(Clock::ProcessDunningCampaignsJob).to have_been_enqueued
+    end
+  end
 end