OpenAPI 3.0.x - validating Path Templating

[char0n]

Every Path Item Object is attached inside Paths Object under patterned field /{path}. The goal of this issue is to validate if the parameters of the Path Item Object contains parameters defined by path templating under the patterned field.

NOTE: note that there is a difference between OpenAPI 2.0 and 3.x.y.
In OpenAPI 2.0 every Paramter Object MUST correspond to the associated path segment from the path field in the Paths Object
In OpenAPI 3.x.y each template expression in the path MUST correspond to a path parameter that is included in the Path Item itself and/or in each of the Path Item's Operations.

TODO:

• make sure this is also properly implemented in OpenAPI 2.0 rules

[char0n]

Looks like duplicate of #3517