Hey there!
I just got some words back from our product managers. Here they are:
The Terraform Provider is not Auth0 software, it is community software. However Auth0 does support interaction with Terraform in all customer tenants including production deployments. It should also be noted that Auth0 is the primary sponsor of that maintainer and those repos and we have active contributors to those.
We plan to extend that relationship with Alex (the main maintainer) in a more formal way but there is no public information on that as of now.