cloudrunv2: Validate number of ports specified restricting to 1. (Goo…

…gleCloudPlatform#10173)

* cloudrunv2: Validate number of ports specified restricting to 1.

* Update mmv1/products/cloudrunv2/Service.yaml

mmv1/products/cloudrunv2/Service.yaml

@@ -448,6 +448,7 @@ properties:
                     Determines whether CPU should be boosted on startup of a new container instance above the requested CPU threshold, this can help reduce cold-start latency.
             - !ruby/object:Api::Type::Array
               name: 'ports'
+              max_size: 1
               description: |-
                 List of ports to expose from the container. Only a single port can be specified. The specified ports must be listening on all interfaces (0.0.0.0) within the container to be accessible.