[REVIEW] Allow CuPy 8.x

[mdemoret-nv]

Both cuML and cuSignal would like to move to cuPy 8 and have done initial testing with it. This change does not eliminate 7.x support, just allows 8.x.

PR for cuml: rapidsai/cuml#2910
PR for integration: rapidsai/integration#139

[GPUtester]

Please update the changelog in order to start CI tests.

View the gpuCI docs here.

[codecov]

Codecov Report

Merging #6409 into branch-0.16 will increase coverage by 0.02%.
The diff coverage is n/a.

@@               Coverage Diff               @@
##           branch-0.16    #6409      +/-   ##
===============================================
+ Coverage        82.96%   82.98%   +0.02%     
===============================================
  Files               94       94              
  Lines            14827    14828       +1     
===============================================
+ Hits             12301    12305       +4     
+ Misses            2526     2523       -3     

Impacted Files	Coverage Δ
python/cudf/cudf/_fuzz_testing/fuzzer.py	0.00% <0.00%> (ø)
python/cudf/cudf/core/abc.py	91.48% <0.00%> (+4.25%)	⬆️
python/cudf/cudf/utils/gpu_utils.py	58.53% <0.00%> (+4.87%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 185fe96...50a73b9. Read the comment docs.