Boost Geo prune worker to run every 2 hours instead of 6

Changes cron schedule for `geo_prune_event_log_worker` from
`0 */6 * * *` to `0 */2 * * *`.

It reduces the average of 600k events deleted every 6h, to 200k events
deleted every 2h:
https://gitlab.com/gitlab-com/infrastructure/issues/4231#note_79874454

Closes gitlab-com/infrastructure#4231.

config/gitlab.yml.example

@@ -294,7 +294,7 @@ production: &base
     # GitLab Geo prune event log worker
     # NOTE: This will only take effect if Geo is enabled (primary node only)
     geo_prune_event_log_worker:
-      cron: "0 */6 * * *"
+      cron: "0 */2 * * *"
 
     # GitLab Geo repository sync worker
     # NOTE: This will only take effect if Geo is enabled (secondary nodes only)

config/initializers/1_settings.rb

@@ -327,7 +327,7 @@ Settings.cron_jobs['geo_file_download_dispatch_worker'] ||= Settingslogic.new({}
 Settings.cron_jobs['geo_file_download_dispatch_worker']['cron'] ||= '*/1 * * * *'
 Settings.cron_jobs['geo_file_download_dispatch_worker']['job_class'] ||= 'Geo::FileDownloadDispatchWorker'
 Settings.cron_jobs['geo_prune_event_log_worker'] ||= Settingslogic.new({})
-Settings.cron_jobs['geo_prune_event_log_worker']['cron'] ||= '0 */6 * * *'
+Settings.cron_jobs['geo_prune_event_log_worker']['cron'] ||= '0 */2 * * *'
 Settings.cron_jobs['geo_prune_event_log_worker']['job_class'] ||= 'Geo::PruneEventLogWorker'
 Settings.cron_jobs['geo_repository_verification_primary_batch_worker'] ||= Settingslogic.new({})
 Settings.cron_jobs['geo_repository_verification_primary_batch_worker']['cron'] ||= '*/1 * * * *'

ee/changelogs/unreleased/tc-geo-boost-prune-worker.yml

+---
+title: Boost Geo prune worker to run every 2 hours instead of 6
+merge_request: 6074
+author:
+type: performance