CompatHelper: bump compat for "JSExpr" to "1"

[github-actions[bot]]

This pull request changes the compat entry for the JSExpr package from 0.4, 0.5 to 0.4, 0.5, 1.

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.

[baumgold]

@pfitzseb - can we merge this one, please? Thanks.