CompatHelper: bump compat for LinearSolve to 3, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the LinearSolve package from 2.4.2 - 2 to 2.4.2 - 2, 3.
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 53.68%. Comparing base (0d0e5d6) to head (a084db5).
Report is 3 commits behind head on main.

❗ There is a different number of reports uploaded between BASE (0d0e5d6) and HEAD (a084db5). Click for more details.

HEAD has 6 uploads less than BASE

Flag	BASE (0d0e5d6)	HEAD (a084db5)
	8	2

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #144       +/-   ##
===========================================
- Coverage   91.77%   53.68%   -38.09%     
===========================================
  Files          24       24               
  Lines        1495     1466       -29     
===========================================
- Hits         1372      787      -585     
- Misses        123      679      +556     

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