CompatHelper: add new compat entry for GLMakie in [weakdeps] at version 0.13, (keep existing compat)

[github-actions]

This pull request sets the compat entry for the GLMakie package to 0.13.
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.
Note: Consider registering a new release of your package immediately after merging this PR, as downstream packages may depend on this for tests to pass.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 54.89%. Comparing base (e1aa9f9) to head (e7cd33d).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #21   +/-   ##
=======================================
  Coverage   54.89%   54.89%           
=======================================
  Files          94       94           
  Lines        6501     6501           
=======================================
  Hits         3569     3569           
  Misses       2932     2932           

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