CompatHelper: bump compat for EvoTrees in [extras] to 0.18, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the EvoTrees package from 0.16 to 0.16, 0.18.
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]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.58%. Comparing base (ad3b1aa) to head (51216b7).
⚠️ Report is 37 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #106      +/-   ##
==========================================
- Coverage   94.46%   91.58%   -2.88%     
==========================================
  Files          24       24              
  Lines         524      535      +11     
==========================================
- Hits          495      490       -5     
- Misses         29       45      +16     

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