Endpoints in Service Directory can be *associated* with a
VPC. In this case, they can be used by supported Google
Cloud products to send requests directly to resources inside
a VPC. This feature is called Private Network Access.
The `google_service_directory_endpoint` resource supports
this configuration with a new argument `network`.
Unfortunately, this argument has an unusual format: it
is similar to a standard VPC ID, but instead of the project ID,
it expects the project number.
Stefano Tribioli
Miren Esnaola
Julio Castillo