CompatHelper: bump compat for DiffEqCallbacks to 4, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the DiffEqCallbacks package from 2.25, 3 to 2.25, 3, 4.
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 69.37%. Comparing base (eb9f41b) to head (62be165).
Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #622   +/-   ##
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  Coverage   69.37%   69.37%           
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  Files          85       85           
  Lines        5124     5124           
=======================================
  Hits         3555     3555           
  Misses       1569     1569           

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unit	69.37% <ø> (ø)

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[sloede]

The tests pass, but they still seem to be using DiffEqCallbacks v3.8.0.

[svchb]

I did run the tests again still 3.8.0.

[svchb]

Still not being used even with 1.11

[svchb]

Done in #632

[efaulhaber]

We should keep in mind that the tests are still using 3 instead of 4.

[svchb]

I checked we are not using any of the changed features at the moment.