CompatHelper: bump compat for JLD2 to 0.5 for package docs, (drop existing compat)

[github-actions[bot]]

This pull request changes the compat entry for the JLD2 package from 0.4 to 0.5 for package docs. This drops 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.