No GPU support for graph convolutions

Hi,

I have the same issue referenced at the end of https://github.com/tensorflow/graphics/issues/13
Namely the ops SparseReshape does not seem to have GPU support.
My code runs fine with automatic device placement but gives this when I force the placement of graph convolutions on gpu0.

[...]
InvalidArgumentError (see above for traceback): Cannot assign a device for operation graph_convolution_feature_steered_convolution_weights/graph_convolution_feature_steered_convolution/utils_convert_to_block_diag_2d/SparseReshape: Could not satisfy explicit device specification '/device:GPU:0' because no supported kernel for GPU devices is available.
Registered kernels:
  device='CPU'

I have the same error on windows and linux with tf 1.15 and cuda 10.