Bump rubocop-rails from 2.5.2 to 2.6.0 (#8643)

Gemfile

@@ -139,7 +139,7 @@ group :development, :test do
   gem "rspec-rails", "~> 4.0" # rspec-rails is a testing framework for Rails 3+
   gem "rubocop", "~> 0.85.1", require: false # Automatic Ruby code style checking tool
   gem "rubocop-performance", "~> 1.6", require: false # A collection of RuboCop cops to check for performance optimizations in Ruby code
-  gem "rubocop-rails", "~> 2.5", require: false # Automatic Rails code style checking tool
+  gem "rubocop-rails", "~> 2.6", require: false # Automatic Rails code style checking tool
   gem "rubocop-rspec", "~> 1.39", require: false # Code style checking for RSpec files
   gem "spring", "~> 2.1" # Preloads your application so things like console, rake and tests run faster
   gem "spring-commands-rspec", "~> 1.0" # rspec command for spring

Gemfile.lock

@@ -105,7 +105,7 @@ GEM
     approvals (0.0.24)
       nokogiri (~> 1.6)
       thor (~> 0.18)
-    ast (2.4.0)
+    ast (2.4.1)
     autoprefixer-rails (9.7.6)
       execjs
     aws-eventstream (1.1.0)
@@ -696,10 +696,10 @@ GEM
       parser (>= 2.7.0.1)
     rubocop-performance (1.6.1)
       rubocop (>= 0.71.0)
-    rubocop-rails (2.5.2)
-      activesupport
+    rubocop-rails (2.6.0)
+      activesupport (>= 4.2.0)
       rack (>= 1.1)
-      rubocop (>= 0.72.0)
+      rubocop (>= 0.82.0)
     rubocop-rspec (1.39.0)
       rubocop (>= 0.68.1)
     ruby-prof (1.4.1)
@@ -979,7 +979,7 @@ DEPENDENCIES
   rspec-retry (~> 0.6)
   rubocop (~> 0.85.1)
   rubocop-performance (~> 1.6)
-  rubocop-rails (~> 2.5)
+  rubocop-rails (~> 2.6)
   rubocop-rspec (~> 1.39)
   ruby-prof (~> 1.4)
   rubyzip (~> 2.3)