Feature Request: Support for OpenAPI v2

[fathiraz]

Hello,

First, I want to express my appreciation for the great work on this library! It has been incredibly useful for my project.

I would like to suggest adding support for OpenAPI v2 in the swagger-markdown tool. Many projects still utilize OpenAPI v2, and having this feature would greatly benefit those users.

Additionally, I noticed that the getkin/kin-openapi library supports OpenAPI v2, which could facilitate the implementation of this feature.

Would you be open to considering this addition?
Thank you!