Add spconv python package rosdep keys

[JWhitleyWork]

Please add the following dependency to the rosdep database.

Package name:

spconv: Spatially Sparce Convolutional Library

Package Upstream Source:

https://github.com/traveller59/spconv

Purpose of using this:

This is a dependency of several SLAM algorithms including hdl_graph_slam and hdl_localization. These provide some of the best results that I've seen for map generation and localization.

Links to Distribution Packages

• https://pypi.org/project/spconv/
• https://pypi.org/project/spconv-cu114/
• https://pypi.org/project/spconv-cu116/
• https://pypi.org/project/spconv-cu117/
• https://pypi.org/project/spconv-cu118/