UUID type not working

Look at the following query:

```
query GetBookByID($id:uuid!) {
getBook(id:$id) {
id
title
author
}
}
```
When you build the project the generated class should have 'id' variable of type "UUID" but instead it is defined as "Uuid" and hence an error is thrown.

Start by reproducing the build with the shown GetBookByID query and inspect the generated class for the id field. Trace the UUID/Uuid type mapping in the code-generation entry point, then verify that the generated field uses UUID and the project builds successfully.

Written by the indexing model from the issue text.