How to get Swashbuckle working on sitefinity 10.x - swagger

Question

I had installed Swashbuckle on Sitefinity 7.x and it was working just fine, after update my Sitefinity project to 10.x it stopped working (getting 500 error). I have tried different version of Swashbuckle with the same setup without success, I have also tried some different Swashbuckle configuration without much luck.
This is the setup code I have in the Sitefinity project's Global.asax (which used to work)
protected void Application_Start(object sender, EventArgs e)
{
Bootstrapper.Initialized += Bootstrapper_Initialized;
}
private void Bootstrapper_Initialized(object sender, ExecutedEventArgs args)
{
RouteTable.Routes.Ignore("ipad");
if (args.CommandName == "RegisterRoutes")
{
RegisterRoutes(RouteTable.Routes);
CustomPageRouteHandler.RegisterType();
GlobalConfiguration.Configuration.Filters.Add(new LoggingFilterAttribute());
GlobalConfiguration.Configuration.Services.Replace(typeof(IHttpActionInvoker), new ControllerActionInvoker());
GlobalConfiguration.Configuration.Filters.Add(new ApiExceptionFilterAttribute());
JsonDefaultSerializer.ConfigureApi(GlobalConfiguration.Configuration);
GlobalConfiguration.Configuration
.EnableSwagger(c =>
{
c.SingleApiVersion("v1", "xxx.Web");
c.DocumentFilter<SwaggerCustomControllersFilter>();
c.IgnoreObsoleteActions();
c.ResolveConflictingActions(apiDescriptions => apiDescriptions.First());
})
.EnableSwaggerUi(c =>
{
c.DisableValidator();
});
GlobalConfiguration.Configuration.EnsureInitialized();
}
}
The following is the error message I am getting:
{
"Message": "An error has occurred.",
"ExceptionMessage": "Object reference not set to an instance of an object.",
"ExceptionType": "System.NullReferenceException",
"StackTrace": " at System.Collections.Generic.DictionaryExtensions.TryGetValue[T](IDictionary2 collection, String key, T& value)
at System.Web.Http.Description.ApiExplorer.ExploreRouteControllers(IDictionary2 controllerMappings, IHttpRoute route)
at System.Web.Http.Description.ApiExplorer.InitializeApiDescriptions()
at System.Lazy1.CreateValue()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Lazy1.get_Value()
at Swashbuckle.Swagger.SwaggerGenerator.GetSwagger(String rootUrl, String apiVersion)
at Swashbuckle.Application.SwaggerDocsHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpMessageInvoker.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Web.Http.Dispatcher.HttpRoutingDispatcher.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.DelegatingHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Web.Http.Cors.CorsMessageHandler.d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Web.Http.HttpServer.d__0.MoveNext()"
}
here are some of the packages versions:
Swashbuckle 5.6.0
Swashbuckle.Core 5.6.0
System.Net.Http 4.3.3
WebActivatorEx 2.2.0