CompatHelper: bump compat for GeometricEquations to 0.18, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the GeometricEquations package from 0.16, 0.17 to 0.16, 0.17, 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 67.01%. Comparing base (66af6a2) to head (761d54f).
Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #162      +/-   ##
==========================================
- Coverage   68.02%   67.01%   -1.01%     
==========================================
  Files         123      123              
  Lines        3740     3747       +7     
==========================================
- Hits         2544     2511      -33     
- Misses       1196     1236      +40     

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