Add email information for gitlab_instance_service_account resource

Update Resource

In the current API, we can use an attribute email to create a service account. It would be nice to add it gitlab_instance_service_account.

resource "gitlab_instance_service_account" "gitlab_sa" {
  name     = "name - Service Account user"
  username = "username_sa"
  mail     = "username@gitlab.com"
}

Related GitLab APIs

API documentation: https://docs.gitlab.com/api/user_service_accounts/#create-a-service-account-user

Additional Details

• GitLab REST API resources available (read for data sources, CRUD for resources)
• client-go supports the related GitLab API already
• I'd like to contribute it myself