Add support for herited action methods

[Kaon68]

Hi there

I've noticed that herited action method does not show the lock icon with SecurityRequirementsOperationFilter.

For the moment, I have bypassed this issue by cloning your SecurityRequirementsOperationFilter (generic and non generic) classes and replaced extension method GetControllerAndActionAttributes by this one :

   public static IEnumerable<T> GetControllerAndActionAttributes<T>(this OperationFilterContext context) where T : Attribute
        {
            var controllerAttributes = context.GetControllerTypeInfos().GetTypeInfo().GetCustomAttributes<T>();
            var actionAttributes = context.MethodInfo.GetCustomAttributes<T>();

            var result = new List<T>(controllerAttributes);
            result.AddRange(actionAttributes);
            return result;
        }

        public static TypeInfo GetControllerTypeInfos(this OperationFilterContext context)
        {
            ControllerActionDescriptor controllerActionDescriptor = context.ApiDescription.ActionDescriptor as ControllerActionDescriptor;
            TypeInfo controllerType = controllerActionDescriptor?.ControllerTypeInfo;
            controllerType ??= context.MethodInfo.DeclaringType?.GetTypeInfo();

            return controllerType;
        }

maybe quick & dirty, but it works ;)