Suggestion: Remove Space in between Folder Names

[YukunJ]

It caught my attention that when trying to use Procgen as a third party dependency, when building in a sandbox Bazel,
the empty space in between Procgen Asset's folder cause some problems. It might be a super nice space left there.

For example,

/data/assets/kenney-abstract/Players)/[space folders]
/data/assets/kenney/Players)/[space folders]

Would that be possible for maintainer to consider replace those space with _ as common practices? Not sure why those spaces are there at first place