message: Make IPUSelectionOrder protobug>=3.6.1 compatible
  Reviewers: #tensorflow, anthonyb
  Subscribers: anthonyb
diff: @@ -120,10 +120,10 @@ class SelectionOrder(Enum):
  The `SNAKE` and `HOOF` IPU selection orders are particularly beneficial for
  pipelined models.
  """
  - AUTO = IPUSelectionOrder.AUTO
  - ZIGZAG = IPUSelectionOrder.ZIGZAG
  - SNAKE = IPUSelectionOrder.SNAKE
  - HOOF = IPUSelectionOrder.HOOF
  + AUTO = IPUSelectionOrder.Value("AUTO")
  + ZIGZAG = IPUSelectionOrder.Value("ZIGZAG")
  + SNAKE = IPUSelectionOrder.Value("SNAKE")
  + HOOF = IPUSelectionOrder.Value("HOOF")
  def configure_ipu_system(config, device="cpu"):
  