WIP: put a ceiling on cuda-python

[jameslamb]

Description

Follow-up to #1720

Contributes to https://github.com/rapidsai/build-planning/issues/116

That PR used != requirements to skip a particular version of cuda-python that rmm was incompatible with. A newer version of cuda-python (12.6.2 for CUDA 12, 11.8.5 for CUDA 11) was just released, and it also causes some build issues for RAPIDS libraries: https://github.com/rapidsai/cuvs/pull/445#issuecomment-2461146449

To unblock CI across RAPIDS, this proposes temporarily switching to ceilings on rmm's cuda-python dependency.

Checklist

• [x] I am familiar with the Contributing Guidelines.
• [x] New or existing tests cover these changes.
• [x] The documentation is up to date with these changes.

[vyasr]

/merge