warning: literal string will be frozen in the future in ruby 3.4.0-preview2

[tmimura39]

Warning by https://bugs.ruby-lang.org/issues/20205

# bundle exec rake minitest
Run options: --seed 23847

# Running:

/ruby-http-client/lib/ruby_http_client.rb:143: warning: literal string will be frozen in the future
...../ruby-http-client/lib/ruby_http_client.rb:143: warning: literal string will be frozen in the future
./ruby-http-client/lib/ruby_http_client.rb:156: warning: literal string will be frozen in the future
./ruby-http-client/lib/ruby_http_client.rb:143: warning: literal string will be frozen in the future
.../ruby-http-client/lib/ruby_http_client.rb:143: warning: literal string will be frozen in the future
.../ruby-http-client/lib/ruby_http_client.rb:143: warning: literal string will be frozen in the future
../ruby-http-client/lib/ruby_http_client.rb:143: warning: literal string will be frozen in the future
.../ruby-http-client/lib/ruby_http_client.rb:143: warning: literal string will be frozen in the future
/ruby-http-client/lib/ruby_http_client.rb:143: warning: literal string will be frozen in the future
/ruby-http-client/lib/ruby_http_client.rb:143: warning: literal string will be frozen in the future
....../ruby-http-client/lib/ruby_http_client.rb:143: warning: literal string will be frozen in the future
.../ruby-http-client/lib/ruby_http_client.rb:143: warning: literal string will be frozen in the future
.../ruby-http-client/lib/ruby_http_client.rb:143: warning: literal string will be frozen in the future
.F./ruby-http-client/lib/ruby_http_client.rb:143: warning: literal string will be frozen in the future
./ruby-http-client/lib/ruby_http_client.rb:143: warning: literal string will be frozen in the future

The choices are these

• Use ''.dup or String.new('') or +''.
• Magic comment frozen_string_literal: false like Shopify/httpclient.
• Ignore warnings until Ruby v3.4 policy is finalized.
• and other...

[chaadow]

Hi @tmimura39 I made a PR that hopefully should resolve the issue