Parse URL Variables

[bl4ckst0ne]

Hey,
In order to support path parameters (for example https://hello.com/example/:someting), Postman uses URL variables.
It is essentially a list of Variable inside the Url object.
There was a declaration for the variable property, but was not parsed.

Therefore, I am adding support for it. 😄

I've tried to follow your code style. Let me know if you've got any problem.

[kirankumbhar]

Hey, @bl4ckst0ne Thank you for the PR. I have reviewed it. While I was going through the schema document, It seems that the default value of variable should be an empty list instead of None.
There are many places the default value needs to be changed.
Can you do it for variable?
So let the default value be empty list and do variable = data.get("variable", [])
Let me know if this is clear to you.

[kirankumbhar]

LGTM

[kirankumbhar]

Thank you @bl4ckst0ne for the contribution!