Is your feature request related to a problem? Please describe.
numpy 2.1 (namely numpy/numpy#26766) changed certain functions to return integer types. This change causes various cudf tests to fail. As a result, cudf currently does not support installation with numpy 2.1. There may be other incompatibilities as well that need to be sorted out.

Describe the solution you'd like
We should resolve the issues and remove the upper bound pin (or rather, move it back to 3.0).