Identity Platform API is inconsistent in version and features with Google Cloud documentation

1) Is this a client library issue or a product issue?

Yes?

2) Did someone already solve this?

No.

3) Do you have a support contract?

Yes, but this doesn't seem like a support issue.

If the support paths suggested above still do not result in a resolution, please provide the following details.

#### Environment details

- OS: all
- Node.js version: all
- npm version: all
- `googleapis` version: all

#### Steps to reproduce

1. Look at Identity Platform documentation online and find that Google Cloud Platform only documents v1, v2: https://cloud.google.com/identity-platform/docs/reference/rest
2. Load up this library, find that you can only access v3, which has a smaller API surface than v1 or v2 and doesn't support APIs like [projects.updateConfig](https://cloud.google.com/identity-platform/docs/reference/rest/v2/projects/updateConfig)
3. Be very confused, why are the API versions different, why doesn't `projects.updateConfig` have a v3 equivalent, et cetera, et cetera.