Merge branch 'fix/oban-pruning' into 'develop'

Bring back oban job pruning

Closes #1945

See merge request pleroma/pleroma!2768

config/config.exs

@@ -512,6 +512,7 @@
     attachments_cleanup: 5,
     new_users_digest: 1
   ],
+  plugins: [Oban.Plugins.Pruner],
   crontab: [
     {"0 0 * * *", Pleroma.Workers.Cron.ClearOauthTokenWorker},
     {"0 * * * *", Pleroma.Workers.Cron.StatsWorker},