Support r2oas_result in RSpec matcher

[yukihirop]

Summary

Implements the rspec matcher that reads the OpenAPI Specification definition and returns the result according to each response.

Image

RSpec.describe  SampleController, type: :controller do
  it { expect(response.body).to eq r2oas_result(:ok) }
  it { expect(response.body).to eq r2oas_result(422) }
end

Run-time results should be displayed in detail.