Downgrade sidekiq to previous version.

Gemfile

@@ -20,9 +20,8 @@ gem "sprockets", "~> 3.7", "< 4"
 gem 'wicked_pdf'
 gem 'letter_opener_web'
 gem 'puma', '>= 3.12.2'
-gem 'sidekiq'
+gem 'sidekiq', '~> 5.2.7'
 gem 'sidekiq-cron'
-gem 'tzinfo-data', platforms: %i(mingw mswin x64_mingw jruby)
 gem 'uglifier', '>= 1.3.0'
 
 group :development, :test do

Gemfile.lock

@@ -639,7 +639,7 @@ GEM
     puma (3.12.2)
     puma (3.12.2-java)
     raabro (1.1.6)
-    rack (2.0.7)
+    rack (2.0.8)
     rack-attack (6.2.1)
       rack (>= 1.0, < 3)
     rack-cors (1.1.0)
@@ -795,11 +795,11 @@ GEM
     selenium-webdriver (3.142.6)
       childprocess (>= 0.5, < 4.0)
       rubyzip (>= 1.2.2)
-    sidekiq (6.0.3)
-      connection_pool (>= 2.2.2)
-      rack (>= 2.0.0)
-      rack-protection (>= 2.0.0)
-      redis (>= 4.1.0)
+    sidekiq (5.2.7)
+      connection_pool (~> 2.2, >= 2.2.2)
+      rack (>= 1.5.0)
+      rack-protection (>= 1.5.0)
+      redis (>= 3.3.5, < 5)
     sidekiq-cron (1.1.0)
       fugit (~> 1.1)
       sidekiq (>= 4.2.1)
@@ -848,8 +848,6 @@ GEM
       nokogiri (>= 1.7.0, <= 2.0)
     tzinfo (1.2.5)
       thread_safe (~> 0.1)
-    tzinfo-data (1.2019.3)
-      tzinfo (>= 1.0.0)
     uber (0.1.0)
     uglifier (4.2.0)
       execjs (>= 0.3.0, < 3)
@@ -928,13 +926,12 @@ DEPENDENCIES
   rails (= 5.2.2)
   rspec-rails (~> 3.7.0)
   rubocop
-  sidekiq
+  sidekiq (~> 5.2.7)
   sidekiq-cron
   spring
   spring-commands-rspec
   spring-watcher-listen (~> 2.0.0)
   sprockets (~> 3.7, < 4)
-  tzinfo-data
   uglifier (>= 1.3.0)
   web-console
   webmock