compatibility with Flux

Hi,
this is to enquire about the possibility of using Interpolations.jl to build image upsampling or downsampling layers in Flux.jl.
We recently added a bilinear upsampling function https://github.com/FluxML/NNlib.jl/pull/262, but I was wondering if we could leverage instead some of the code here. The requisites would be

- handle batch dimension
- gradient computation
- compatible with CuArrays

I'm not familiar with the codebase here, maybe this is a long shot, but worth making an attempt and creating awareness about the possibility of this kind of interaction.
Moreover gpu and automatic diff friendly interpolations would generally benefit the ML ecosystem.

Best,
CL

cc @johnnychen94