Add support for optional parameters via the --optional-nullable-parameters CLI argument

[christianhelle]

This implements #157

The changes here introduces the new --optional-nullable-parameters command line argument which reorders the method arguments in the generated refit interface and places all nullable parameters at the end so that they are optional

The following OpenAPI spec:

openapi: '3.0.0'
paths:
  /job/{Id}:
    post:
      tags:
      - 'Jobs'
      operationId: 'Update job details'
      description: 'Update the details of the specified job.'
      parameters:
        - in: 'path'
          name: 'Id'
          description: 'Foo Id'
          required: true
          schema:
            type: 'string'
        - in: 'query'
          name: 'Title'
          description: 'Job title'
          nullable: true
          schema:
            type: 'string'
        - in: 'query'
          name: 'Description'
          description: 'Job description'
          nullable: true
          schema:
            type: 'string'
        - in: 'query'
          name: 'Contact'
          description: 'Contact Person'
          nullable: true
          schema:
            type: 'string'
      responses:
        '200':
          description: 'successful operation'

generates the following code:

public partial interface IApiClient
{
    /// <summary>
    /// Update the details of the specified job.
    /// </summary>
    [Post("/job/{Id}")]
    Task UpdateJobDetails(
        [AliasAs("Id")] string id, 
        [Query, AliasAs("Title")] string? title = default, 
        [Query, AliasAs("Description")] string? description = default, 
        [Query, AliasAs("Contact")] string? contact = default, 
        CancellationToken cancellationToken = default);
}

[codecov]

Codecov Report

Merging #163 (3467f6b) into main (65ab097) will decrease coverage by 0.16%.
Report is 1 commits behind head on main.
The diff coverage is 95.16%.

@@            Coverage Diff             @@
##             main     #163      +/-   ##
==========================================
- Coverage   98.41%   98.25%   -0.16%     
==========================================
  Files          39       40       +1     
  Lines        1260     1317      +57     
==========================================
+ Hits         1240     1294      +54     
  Misses          6        6              
- Partials       14       17       +3     

Flag	Coverage Δ
unittests	98.25% <95.16%> (-0.16%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
src/Refitter.Core/ParameterExtractor.cs	93.54% <85.00%> (-4.28%)	⬇️
src/Refitter.Core/RefitGenerator.cs	99.33% <100.00%> (+0.02%)	⬆️
....Tests/Examples/OptionalNullableParametersTests.cs	100.00% <100.00%> (ø)
src/Refitter.Tests/SwaggerPetstoreTests.cs	99.35% <100.00%> (ø)

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
1 Code Smell

No Coverage information
0.0% Duplication

[waylonmtz]

Works great!