Add userinfo-email scope to VM service account

[minhluantran017]

What feature do you want to see added?

I'm using GCE plugin to provision Jenkins agents and trying to configure RBAC for them against my GKE cluster following docs on https://cloud.google.com/kubernetes-engine/docs/how-to/role-based-access-control.

The document points out that it needs userinfo-email scope so that the RoleBinding (and/or ClusterRoleBinding) can use the service account email instead of a numeric string of service account ID for its definition)

This feature request is to add the userinfo-email scope to the scopes of VM service account when provisioning Jenkins agent.

The userinfo-email scope is a read-only scope top get primary Google Account email address so it should be safe to add to this plugin.

Scope URL: https://www.googleapis.com/auth/userinfo.email
GKE docs: https://cloud.google.com/kubernetes-engine/docs/how-to/role-based-access-control#forbidden_error_for_service_accounts_on_vm_instances

Upstream changes

No response

Are you interested in contributing this feature?

I'm happy to make this change.