tuf-on-ci-sign does not show when timestamp signing period changes

[jku]

I changed the timestamp signing period. When signing this was not made clear in the output:

root v10
 * Modified online delegations timestamp & snapshot
   * Signers: 1/1 of ['gcpkms']
     (was: 1/1 of ['gcpkms']

This really should include signing and expiry period (like it does for other roles)

I guess it would be something like

root v10
 * Modified online delegations timestamp & snapshot
   * Signers: 1/1 of ['gcpkms']
     (was: 1/1 of ['gcpkms']
   * Expiry period: 7 days, signing period: 1 days
     (expiry period was 7 days, signing period was 4 days