Fix warnings in test_monotonic.py

[vyasr]

Description

One note with these deprecations. pandas has a special value used for parameters that are defaulted, and as a result explicitly passing None will throw a warning. We don't do this, hence the difference in the warnings contexts I use for our calls vs pandas (pytest.warns vs expect_warning_if). I didn't feel like this was worth commenting on in every place, but I can if reviewers want.

Contributes to #9999 and #10363.

Checklist

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

[codecov]

Codecov Report

Base: 88.37% // Head: 86.04% // Decreases project coverage by -2.32% ⚠️

Coverage data is based on head (8eede18) compared to base (a9f9958).
Patch coverage: 95.60% of modified lines in pull request are covered.

Additional details and impacted files

@@               Coverage Diff                @@
##           branch-23.02   #12334      +/-   ##
================================================
- Coverage         88.37%   86.04%   -2.33%     
================================================
  Files               137      155      +18     
  Lines             22657    25421    +2764     
================================================
+ Hits              20022    21873    +1851     
- Misses             2635     3548     +913     

Impacted Files	Coverage Δ
python/cudf/cudf/core/column/column.py	87.95% <ø> (-0.03%)	⬇️
python/cudf/cudf/core/dataframe.py	93.49% <66.66%> (-0.18%)	⬇️
python/cudf/cudf/core/_base_index.py	81.38% <100.00%> (+0.22%)	⬆️
python/cudf/cudf/core/column_accessor.py	97.02% <100.00%> (+0.04%)	⬆️
python/cudf/cudf/core/index.py	94.10% <100.00%> (+1.17%)	⬆️
python/cudf/cudf/core/indexed_frame.py	92.44% <100.00%> (+0.30%)	⬆️
python/cudf/cudf/core/join/_join_helpers.py	98.52% <100.00%> (-0.07%)	⬇️
python/cudf/cudf/core/join/join.py	94.24% <100.00%> (+0.12%)	⬆️
python/cudf/cudf/core/multiindex.py	92.23% <100.00%> (+0.05%)	⬆️
python/cudf/cudf/core/reshape.py	83.40% <100.00%> (+0.03%)	⬆️
... and 23 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[bdice]

Minor suggestion, otherwise LGTM.

[vyasr]

@gpucibot merge