Fix missing support for Query Parameters

[christianhelle]

The changes here add's the missing Query parameters support in the generated Refit interface

Endpoints that use query parameters will be generated like this:

[Get("/pet/findByStatus")]
Task<ICollection<Pet>> FindPetsByStatus([Query]Status? status);

[Get("/pet/findByTags")]
Task<ICollection<Pet>> FindPetsByTags([Query(CollectionFormat.Multi)]ICollection<string> tags);

This was verified using the Swagger Petstore v3 OpenAPI specifications and tested using the following code:

var client = RestService.For<ISwaggerPetstore>("https://petstore3.swagger.io/api/v3");
var pet = await client.GetPetById(2);

Console.WriteLine($"Name: {pet.Name}");
Console.WriteLine($"Category: {pet.Category.Name}");
Console.WriteLine($"Status: {pet.Status}");

var pets = await client.FindPetsByStatus(Status.Available);
Console.WriteLine("Found " + pets.Count + " available pet(s)");        

var taggedPets = await client.FindPetsByTags(new[] {"tag1Updated", "new"});
Console.WriteLine("Found " + taggedPets.Count + " tagged pet(s)");

Which when executed returns the following text:

Name: Gatitotototo
Category: Chaucito
Status: Sold
Found 44 available pet(s)
Found 9 tagged pet(s)

This resolves #5