Implement detection rules for adding new required header parameters in request

[phoebey01]

The current rules only account for newly added required parameters in the objects sent in a request, but no the request header. For example, when the api has a newly required header parameter, it could be a backward incompatible change for users sending requests that were accepted by the old api.

[macisamuele]

@yyang08 you're definitely correct

The tool was initially drafted to account for the "usual" backward incompatible changes that we were experiencing at Yelp 😅 .
Swagger specs are very expressive and flexible, but at the same time a lot of possible changes might break compatibility.
The idea of the tool is to provide a base-ground to implement the different detection rules.

I'm not sure on when I might have bandwidth to look into this by providing a PR, but we're always looking for and welcoming contributors 😄

A good starting point for the implementation of new rules might be found in the README