CompatHelper: bump compat for "PackageCompiler" to "2.0"

[github-actions[bot]]

This pull request changes the compat entry for the PackageCompiler package from 1.2.5 to 1.2.5, 2.0.

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.