Compatibility issues with Ruby greater or equal to 2.7

[hgeorgilas]

I tried using this gem with Ruby 2.7.1 and I got the following error

#<FrozenError: can't modify frozen String: "">

It seems the issue is the http.rb version dependency you declare in your gemspec file.

spec.add_dependency 'http', '~> 3.0'

This issue seems to be fixed on the 4.2.1 version of http.rb

Maybe bumping the dependency version would be enough.

Full Stack trace

".rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/http-3.3.0/lib/http/response/body.rb:52:in `force_encoding'",
 ".rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/http-3.3.0/lib/http/response/body.rb:52:in `to_s'",
 ".rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/bundler/gems/faraday-http-80c9bedffbb2/lib/faraday/adapter/http.rb:29:in `perform_request'",
 ".rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/bundler/gems/faraday-http-80c9bedffbb2/lib/faraday/adapter/http.rb:16:in `call'",
 ".rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/faraday_middleware-1.0.0/lib/faraday_middleware/response_middleware.rb:36:in `call'",
 ".rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/faraday_middleware-1.0.0/lib/faraday_middleware/response/follow_redirects.rb:79:in `perform_with_redirection'",
 ".rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/faraday_middleware-1.0.0/lib/faraday_middleware/response/follow_redirects.rb:67:in `call'",
 ".rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/faraday-1.0.1/lib/faraday/request/retry.rb:148:in `call'",
 ".rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/faraday-1.0.1/lib/faraday/request/url_encoded.rb:25:in `call'",
 ".rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/faraday-1.0.1/lib/faraday/rack_builder.rb:153:in `build_response'",
 ".rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/faraday-1.0.1/lib/faraday/connection.rb:492:in `run_request'",
 ".rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/faraday-1.0.1/lib/faraday/connection.rb:198:in `get'",

Thanks

EDIT:
Cloned the repo locally, updated gemspec dependency of http.rb to
spec.add_dependency 'http', '~> 4' specs seems to be passing.
Have not tested further than that though.

[olleolleolle]

Please make a PR, it'd help a lot!

[hgeorgilas]

@olleolleolle PR opened #21