…bit indexing) (#1087)

closes #1076

CuPy recently updated `cupyx.scipy.ndimage.label` to support 64-bit indexing when necessary to support large image sizes. See a more detailed description for the changes made in the upstream PR:
cupy/cupy#9859

This MR makes the exact same change to the very similar kernels underlying `cucim.skimage.measure.label`. The reason we don't use CuPy kernels directly for cuCIM's `label` is that the CuPy API is for binary image labeling only (i.e. all foreground pixels are treated the same regardless of intensity). The version of `label` in the scikit-image API also supports a grayscale mode where neighboring pixels are only connected if the grayscale intensity is actually equal. Thus we have modified kernels that support that logic. The indexing concern and solution is the same as in the upstream PR, though.

Authors:
  - Gregory Lee (https://github.com/grlee77)
  - https://github.com/jakirkham

Approvers:
  - https://github.com/jakirkham

URL: #1087