Bump sidekiq from 5.2.9 to 6.2.0

Bumps [sidekiq](https://github.com/mperham/sidekiq) from 5.2.9 to 6.2.0.
- [Release notes](https://github.com/mperham/sidekiq/releases)
- [Changelog](https://github.com/mperham/sidekiq/blob/master/Changes.md)
- [Commits](sidekiq/sidekiq@v5.2.9...v6.2.0)

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

Gemfile.lock

@@ -108,8 +108,6 @@ GEM
     rack (2.2.3)
     rack-mini-profiler (2.3.1)
       rack (>= 1.2.0)
-    rack-protection (2.0.5)
-      rack
     rack-proxy (0.6.5)
       rack
     rack-test (1.1.0)
@@ -144,7 +142,7 @@ GEM
     rb-fsevent (0.10.4)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    redis (3.3.5)
+    redis (4.2.5)
     rspec-core (3.10.1)
       rspec-support (~> 3.10.0)
     rspec-expectations (3.10.1)
@@ -173,11 +171,10 @@ GEM
       sprockets-rails
       tilt
     semantic_range (2.3.1)
-    sidekiq (5.2.9)
-      connection_pool (~> 2.2, >= 2.2.2)
+    sidekiq (6.2.0)
+      connection_pool (>= 2.2.2)
       rack (~> 2.0)
-      rack-protection (>= 1.5.0)
-      redis (>= 3.3.5, < 4.2)
+      redis (>= 4.2.0)
     spring (2.1.1)
     sprockets (4.0.2)
       concurrent-ruby (~> 1.0)