CompatHelper: bump compat for JLArrays to 0.3 for package test, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the JLArrays package from 0.2.0 to 0.2.0, 0.3 for package test.
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 75.93%. Comparing base (2d4d65e) to head (1a1f987).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #74   +/-   ##
=======================================
  Coverage   75.93%   75.93%           
=======================================
  Files           9        9           
  Lines         698      698           
=======================================
  Hits          530      530           
  Misses        168      168           

Flag	Coverage Δ
docs	30.48% <ø> (-4.87%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

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

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.