Fix baseline choice parameter

[timokau]

Description

I believe this fixes #127, though I'm not entirely sure what the intended behaviour of the baseline choice function is. Why does it expect Y on predict? Even if it is a baseline and simply predicts the mean, shouldn't it take Y on fit instead?

Motivation and Context

127

How Has This Been Tested?

Testsuite, pre-commit hooks.

Does this close/impact existing issues?

Fixes #127.

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my changes.

[codecov[bot]]

Codecov Report

Merging #134 into master will decrease coverage by 0.01%. The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #134      +/-   ##
==========================================
- Coverage   59.97%   59.96%   -0.02%     
==========================================
  Files         116      116              
  Lines        7656     7658       +2     
==========================================
  Hits         4592     4592              
- Misses       3064     3066       +2     

Impacted Files	Coverage Δ
csrank/choicefunction/baseline.py	36.36% <0.00%> (-2.35%)	:arrow_down: