CompatHelper: bump compat for Optimisers to 0.4, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the Optimisers package from 0.3 to 0.3, 0.4.
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 94.96%. Comparing base (926f37c) to head (0c9b7a8).

Additional details and impacted files

@@           Coverage Diff           @@
##             main       #7   +/-   ##
=======================================
  Coverage   94.96%   94.96%           
=======================================
  Files           3        3           
  Lines         139      139           
=======================================
  Hits          132      132           
  Misses          7        7           

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