v0.44.0

• datastore:
  • Interface elements whose underlying types are supported, are now supported.
  • Reduce time to initial retry from 1s to 100ms.
• firestore:
  • Add Increment transformation.
• storage:
  • Allow emulator with STORAGE_EMULATOR_HOST.
  • Add methods for HMAC key management.
• pubsub:
  • Add PublishCount and PublishLatency measurements.
  • Add DefaultPublishViews and DefaultSubscribeViews for convenience of
    importing all views.
  • Add add Subscription.PushConfig.AuthenticationMethod.
• spanner:
  • Allow emulator usage with SPANNER_EMULATOR_HOST.
  • Add cloud.google.com/go/spanner/spannertest, a spanner emulator.
  • Add cloud.google.com/go/spanner/spansql which contains types and a parser
    for the Cloud Spanner SQL dialect.
• asset:
  • Add apiv1p2beta1 client.