…gured (#82) (#123)

* Fix token renewals when TokenPolicies have been configured (#82)

* Fix token renewals when TokenPolicies have been configured

When `TokenPolicies` have been configured for a GCP auth role the logic
compared role `Policies` to the request auth's policies. However, it
should have instead looked at the `TokenPolicies` which gets updated if
`TokenPolicies` were not configured and the `Policies` array is > 0.

* Add token renewal test

Tests that a role configured with `policies` can be updated to
`token_policies` and renewals will continue to function correctly.

* Fix error in renewal test (#124)

Co-authored-by: Matt Greenfield <matt.greenfield@datadoghq.com>