message: Added double and UINT64 support to Tensor for mlmodel compat.
  Added UINT32 for completeness.
diff: @@ -196,6 +196,9 @@ message TensorProto {
  // Advanced types
  FLOAT16 = 10;
  + DOUBLE = 11; // double
  + UINT32 = 12; // uint32_t
  + UINT64 = 13; // uint64_t;
  // Future extensions go here.
  }
  @@ -245,6 +248,14 @@ message TensorProto {
  // that in some cases (e.g. int data), protobuf does a better packing via
  // variable length storage, and may lead to smaller binary footprint.
  optional bytes raw_data = 9;
  +
  + // For double
  + // When this field is present, the data_type field MUST be DOUBLE
  + repeated double double_data = 10 [packed = true];
  +
  + // For uint64
  + // When this field is present, the data_type field MUST be UINT64 or UINT32
  + repeated double uint64_data = 11 [packed = true];
  }
  // A sparse tensor must be stored as three dense tensors:
  