Order.API project Mediator error solved.

src/Services/Ordering/Ordering.API/Application/Behaviors/ValidatorBehavior.cs

@@ -1,6 +1,7 @@
 namespace Microsoft.eShopOnContainers.Services.Ordering.API.Application.Behaviors;
 
 public class ValidatorBehavior<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse>
+                : where TRequest : IRequest<TResponse>
 {
     private readonly ILogger<ValidatorBehavior<TRequest, TResponse>> _logger;
     private readonly IEnumerable<IValidator<TRequest>> _validators;