remove non-existing rubocop and yard rake tasks

Author: senid231

Rakefile

@@ -2,17 +2,7 @@
 
 require 'bundler/gem_tasks'
 require 'rspec/core/rake_task'
-require 'rubocop/rake_task'
-require 'yard'
-require 'yard/rake/yardoc_task'
 
 RSpec::Core::RakeTask.new(:spec)
-RuboCop::RakeTask.new(:rubocop)
-YARD::Rake::YardocTask.new(:yard) do |task|
-  task.options += [
-      %(--output-dir=./docs/.vuepress/public/api/),
-      %(--title=Capybara Active Admin API Reference)
-  ]
-end
 
-task default: [:rubocop, :spec]
+task default: [:spec]