Bump sidekiq from 5.1.2 to 5.1.3 (#582)

Bumps [sidekiq](https://github.com/mperham/sidekiq) from 5.1.2 to 5.1.3.
- [Release notes](https://github.com/mperham/sidekiq/releases)
- [Changelog](https://github.com/mperham/sidekiq/blob/master/Changes.md)
- [Commits](https://github.com/mperham/sidekiq/compare/v5.1.2...v5.1.3)

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

Gemfile.lock

@@ -241,7 +241,7 @@ GEM
     sawyer (0.8.1)
       addressable (>= 2.3.5, < 2.6)
       faraday (~> 0.8, < 1.0)
-    sidekiq (5.1.2)
+    sidekiq (5.1.3)
       concurrent-ruby (~> 1.0)
       connection_pool (~> 2.2, >= 2.2.0)
       rack-protection (>= 1.5.0)