CompatHelper: bump compat for StatsBase to 0.34, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the StatsBase package from 0.33 to 0.33, 0.34.
This keeps the compat entries for earlier versions.

Note: I have not tested your package with this new compat entry.
It is your responsibility to make sure that your package tests pass before you merge this pull request.

[codecov-commenter]

Codecov Report

Merging #154 (60d566a) into main (ddc9cc4) will decrease coverage by 0.20%.
The diff coverage is n/a.

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@@            Coverage Diff             @@
##             main     #154      +/-   ##
==========================================
- Coverage   88.65%   88.46%   -0.20%     
==========================================
  Files          13       13              
  Lines         564      598      +34     
==========================================
+ Hits          500      529      +29     
- Misses         64       69       +5     

see 10 files with indirect coverage changes