package:googleapis_auth v2.1.0-beta.1

• Add serviceAccountCredentials getter to AuthClient
• Added parsing for project_id and universe_domain properties for ServiceAccountCredentials
• Add sign() method to ServiceAccountCredentials for RSA-SHA256 signing
• Add IAMSigner class for signing via IAM Credentials API
• Add clientViaServiceAccountImpersonation() function and ImpersonatedAuthClient class for service account impersonation via IAM Credentials API
• Add AuthClientSigningExtension extension on AuthClient providing a universal sign() method that works across all auth contexts (service accounts, ADC, impersonated credentials)
• Require meta: ^1.0.2
• Require sdk: ^3.9.0
• Drop unneeded args dependency.
• Export RSAPrivateKey which is exposed by ServiceAccountCredentials.