Run Rubocop on Rakefile (#23871)

.rubocop.yml

@@ -24,7 +24,6 @@ AllCops:
   Exclude:
     - db/schema.rb
     - 'bin/*'
-    - 'Rakefile'
     - 'node_modules/**/*'
     - 'Vagrantfile'
     - 'vendor/**/*'

Rakefile

@@ -1,6 +1,8 @@
+# frozen_string_literal: true
+
 # Add your own tasks in files placed in lib/tasks ending in .rake,
 # for example lib/tasks/capistrano.rake, and they will automatically be available to Rake.
 
-require File.expand_path('../config/application', __FILE__)
+require File.expand_path('config/application', __dir__)
 
 Rails.application.load_tasks