Bump sidekiq from 5.2.5 to 5.2.6 (mastodon#10582)

Bumps [sidekiq](https://github.com/mperham/sidekiq) from 5.2.5 to 5.2.6.
- [Release notes](https://github.com/mperham/sidekiq/releases)
- [Changelog](https://github.com/mperham/sidekiq/blob/master/Changes.md)
- [Commits](sidekiq/sidekiq@v5.2.5...v5.2.6)

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

Gemfile.lock

@@ -554,7 +554,7 @@ GEM
     scss_lint (0.57.1)
       rake (>= 0.9, < 13)
       sass (~> 3.5, >= 3.5.5)
-    sidekiq (5.2.5)
+    sidekiq (5.2.6)
       connection_pool (~> 2.2, >= 2.2.2)
       rack (>= 1.5.0)
       rack-protection (>= 1.5.0)