message: Add v2 upgrade for:
  tf.nn.weighted_cross_entropy_with_logits
  -tf.nn.sparse_softmax_cross_entropy_with_logits
diff: @@ -440,6 +440,12 @@ class TFAPIChangeSpec(ast_edits.APIChangeSpec):
  "tensor": "data",
  "family": None,
  },
  + "tf.nn.weighted_cross_entropy_with_logits": {
  + "targets": "labels",
  + },
  + "tf.nn.sparse_softmax_cross_entropy_with_logits": {
  + "_sentinel": None,
  + },
  }
  # pylint: disable=line-too-long
  