Merge pull request #2395 from ritikesh/0-10-stable

remove explicit require for thread_safe

Author: bf4

Gemfile

@@ -83,7 +83,6 @@ group :test do
   gem 'm', '~> 1.5'
   gem 'pry', '>= 0.10'
   gem 'byebug', '~> 8.2' if RUBY_VERSION < '2.2'
-  gem 'pry-byebug', platforms: :ruby
 end
 
 group :development, :test do

lib/active_model/serializer.rb

@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 
-require 'thread_safe'
 require 'jsonapi/include_directive'
 require 'active_model/serializer/collection_serializer'
 require 'active_model/serializer/array_serializer'