update doc

Author: weizhouapache

website/docs/d/vpc.html.markdown

@@ -14,6 +14,7 @@ Use this datasource to get information about a vpc for use in other resources.
 
 ```hcl
 data "cloudstack_vpc" "vpc-data-source"{
+    project = "project-1"
     filter{
     name = "name"
     value= "test-vpc"
@@ -27,6 +28,7 @@ data "cloudstack_vpc" "vpc-data-source"{
 ### Argument Reference
 
 * `filter` - (Required) One or more name/value pairs to filter off of. You can apply filters on any exported attributes.
+* `project` - (Optional) The name or ID of the project the vpc belongs to.
 
 ## Attributes Reference
 
@@ -38,4 +40,4 @@ The following attributes are exported:
 * `vpc_offering_name` - Vpc offering name the VPC is created from.
 * `network_domain` - The network domain of the VPC.
 * `project` - The project name of the VPC.
-* `zone_name` - The name of the zone the VPC belongs to.
+* `zone_name` - The name of the zone the VPC belongs to.