Merge branch 'upgrade-sidekiq' into 'master'

Upgrade to Sidekiq 6.4

See merge request gitlab-org/gitlab!79009

Gemfile

@@ -195,7 +195,7 @@ gem 'state_machines-activerecord', '~> 0.8.0'
 gem 'acts-as-taggable-on', '~> 9.0'
 
 # Background jobs
-gem 'sidekiq', '~> 6.3'
+gem 'sidekiq', '~> 6.4'
 gem 'sidekiq-cron', '~> 1.2'
 gem 'redis-namespace', '~> 1.8.1'
 gem 'gitlab-sidekiq-fetcher', '0.8.0', require: 'sidekiq-reliable-fetch'

Gemfile.lock

@@ -201,7 +201,7 @@ GEM
     colored2 (3.1.2)
     commonmarker (0.23.2)
     concurrent-ruby (1.1.9)
-    connection_pool (2.2.2)
+    connection_pool (2.2.5)
     contracts (0.11.0)
     cork (0.3.0)
       colored2 (~> 3.1)
@@ -1174,7 +1174,7 @@ GEM
     shellany (0.0.1)
     shoulda-matchers (4.0.1)
       activesupport (>= 4.2.0)
-    sidekiq (6.3.1)
+    sidekiq (6.4.0)
       connection_pool (>= 2.2.2)
       rack (~> 2.0)
       redis (>= 4.2.0)
@@ -1620,7 +1620,7 @@ DEPENDENCIES
   sentry-raven (~> 3.1)
   settingslogic (~> 2.0.9)
   shoulda-matchers (~> 4.0.1)
-  sidekiq (~> 6.3)
+  sidekiq (~> 6.4)
   sidekiq-cron (~> 1.2)
   simple_po_parser (~> 1.1.2)
   simplecov (~> 0.18.5)