Build(deps): Bump mini_scheduler from 0.12.2 to 0.12.3 (#10931)

Bumps [mini_scheduler](https://github.com/discourse/mini_scheduler) from 0.12.2 to 0.12.3.
- [Release notes](https://github.com/discourse/mini_scheduler/releases)
- [Changelog](https://github.com/discourse/mini_scheduler/blob/master/CHANGELOG.md)
- [Commits](https://github.com/discourse/mini_scheduler/compare/v0.12.2...v0.12.3)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Gemfile.lock

@@ -187,7 +187,7 @@ GEM
     mini_portile2 (2.4.0)
     mini_racer (0.3.1)
       libv8 (~> 8.4.255)
-    mini_scheduler (0.12.2)
+    mini_scheduler (0.12.3)
       sidekiq
     mini_sql (0.3)
     mini_suffix (0.3.0)