feat: merge path

[MaurerKrisztian]

Enable to merge paths.

doc.addPath('/users', {
  post: {...}
});

doc.mergePath('/users', {
  get: {...}
});

doc.mergePath('/users', {
  delete: {...}
});

// didn't overwrite "/users" as the "addPath" does, merging with the existing ones
/** result
{
  post: {...}
  get: {...}
  delete: {...}
}

*/

[pjmolina]

Hi. Thanks for the PR @MaurerKrisztian
Can be implement addPath directly in the way you implemented it? I think so.
That way it will not introduce a new method: no need for the user to know if the the path was already inserted or not.
A test for it would be super-nice also to ensure the semantics are preserved.

[MaurerKrisztian]

Hi @pjmolina, I didn't want to break something that's why I implemented it as a separate method. I added the requested changes. Hope you like it.

[pjmolina]

Superb! Looks great. Thank you and merging!

[pjmolina]

Thank you again @MaurerKrisztian. Your fix is now published on openapi3-ts@3.1.2.