title: 'SwaggerGenOptions' does not contain a definition for 'SerializeAsV2'
body: <p>I'm trying to use swaggergen tools, so I configure my services:</p>
  
  <pre><code>        services.AddSwaggerGen(c =&gt;
          {
              c.SerializeAsV2 = true;
              c.CustomOperationIds(apiDescription =&gt; {
                  return apiDescription.TryGetMethodInfo(out MethodInfo methodInfo) ? methodInfo.Name : null;
              });
  </code></pre>
  
  <p>I have Swashbuckle.AspNetCore and Swashbuckle.AspNetCore.Newtonsoft installed in my nuget package manager</p>
  
  <p>Why does the c.SerializeAsV2 has a red squiggly: "'SwaggerGenOptions' does not contain a definition for 'SerializeAsV2'" I can't find anything on this at all in google.</p>