[RUBY] Replace deprecated URI.encode to support ruby 2.7 without warnings

[kitop]

PR checklist

• Read the contribution guidelines.
• Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh and ./bin/security/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\.
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Description of the PR

Issue: #10444

Ruby's URI.encode has been deprecated over 10 years ago. In addition, Ruby 2.7 now shows the warning in non-verbose mode, resulting in very noisy logs.

This tackles the problem via the second solution proposed in the issue.
It adds a dependency on the addressable gem, and uses Addressable::URI.encode which is part-aware.

Already tried this in a generated library with success: https://github.com/netlify/zuora-ruby-client/pull/7/files

/cc @zlx

[kitop]

Tests are failing due to un unrelated change in Typhoeus: typhoeus/typhoeus#575
Typhoeus::Response::Header no longer inherits from Hash, but now is a DelegateClass(Hash). And since it's checking the type in https://github.com/kitop/swagger-codegen/blob/5236247dce2ac814a71a031763aa78959d42b424/samples/client/petstore/ruby/spec/pet_spec.rb#L82 it fails.

An option would be to change that check, or another one, to call to_h here: https://github.com/kitop/swagger-codegen/blob/5236247dce2ac814a71a031763aa78959d42b424/samples/client/petstore/ruby/lib/petstore/api_client.rb#L66

Thoughts?

[kitop]

Pushed the second option to have the test passing. Let me know if you'd prefer an alternative, or a separate PR.

[HugoMario]

Thanks a lot for PR @kitop!! Here is fine :)