cloudrunv2: Validate number of ports specified restricting to 1. (#10173) (#17594)

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

* Update mmv1/products/cloudrunv2/Service.yaml

[upstream:219ab589aaafa919c7011967def03305f56c8462]

Signed-off-by: Modular Magician <[email protected]>

Author: modular-magician

.changelog/10173.txt

@@ -0,0 +1,3 @@
+```release-note:enhancement
+cloudrunv2: added the validation to restrict number of ports to 1 to fail earlier than server-side validation
+```

google/services/cloudrunv2/resource_cloud_run_v2_service.go

@@ -301,6 +301,7 @@ is the value of container.ports[0].containerPort.`,
 										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.
 
 If omitted, a port number will be chosen and passed to the container through the PORT environment variable for the container to listen on`,
+										MaxItems: 1,
 										Elem: &schema.Resource{
 											Schema: map[string]*schema.Schema{
 												"container_port": {