Values:
ROLLOUT_STATUS_UNSPECIFIED (0):
No status specified.
IN_PROGRESS (1):
The Rollout is in progress.
SUCCESS (2):
The Rollout has completed successfully.
CANCELLED (3):
The Rollout has been cancelled. This can
happen if you have overlapping Rollout pushes,
and the previous ones will be cancelled.
FAILED (4):
The Rollout has failed and the rollback
attempt has failed too.
PENDING (5):
The Rollout has not started yet and is
pending for execution.
FAILED_ROLLED_BACK (6):
The Rollout has failed and rolled back to the
previous successful Rollout.
