Use latest pylint + Remove outdated docstring

[hcho3]

• Reduce positional arguments to 4 per function.
• Show a deprecation notice whenever the user uses a public function with too many positional arguments.
• Treelite now supports HistGradientBoostingRegressor with categorical features. Remove an outdated docstring.

[codecov]

Codecov Report

Attention: Patch coverage is 84.61538% with 6 lines in your changes missing coverage. Please review.

Project coverage is 84.80%. Comparing base (bf9c75a) to head (55559f2).
Report is 8 commits behind head on mainline.

Files with missing lines	Patch %	Lines
python/treelite/util.py	81.25%	6 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           mainline     #586      +/-   ##
============================================
- Coverage     84.82%   84.80%   -0.02%     
============================================
  Files            75       75              
  Lines          6549     6587      +38     
  Branches        528      528              
============================================
+ Hits           5555     5586      +31     
- Misses          994     1001       +7     

Flag	Coverage Δ
	84.80% <84.61%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.