Add cuda-python dependency to pyproject.toml

[sevagh]

When trying to install rmm with pip using the git url, I ran into some Cython CUDA compile errors:

(rapids) root@5a38f55ffbdd:/rmm/python#  pip install -e 'git+https://github.com/rapidsai/rmm.git@branch-22.04#egg=rmm&subdirectory=python'
...
/src/rmm/python/rmm/_lib/cuda_stream.pxd:16:0: 'cuda/ccudart.pxd' not found
        Error compiling Cython file:
        ------------------------------------------------------------
        cimport cython
        from cuda.ccudart cimport cudaStream_t
        ^
...

Adding cuda-python to the pyproject.toml requires (as suggested by @vyasr and @shwina) helped solve the issue:

(rapids) root@5a38f55ffbdd:/rmm/python# pip install .
Processing /rmm/python
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
  Preparing metadata (pyproject.toml) ... done
...
(rapids) root@5a38f55ffbdd:/rmm/python# python -c 'import rmm; buf = rmm.DeviceBuffer(size=100); print(buf.size); print(buf.ptr)'
100
140379508703232
(rapids) root@5a38f55ffbdd:/rmm/python#

[shwina]

@gpucibot merge

[jakirkham]

Thanks Sevag! 😄