Add summary property in ApiResponse

[ymohdriz]

Hi team,

I have added the summary property in ApiResponse class.
Detailed issue description: https://github.com/OAI/OpenAPI-Specification/issues/1591

I request you to do the code review and inform me if any changes are required.

Thanks,
Mohammed Rizwan

[frantuma]

Link to issue above is broken, good one should be this one. However that points to an open discussion about spec enhancements which is not part of any released spec, it's therefore too early to address it in implementations, and I will close this PR for the time being

[ymohdriz]

Hi @frantuma,

Thanks for the clarification.

Thanks,
Mohammed