Update setuptools

[aljazerzen]

PR #101 has pinned setuptools to <70.2

It should be updated to a recent version (but not just * or >77).

I've tried that in #152, but there are build failures from other packages in the build process. This should be fixed before we get to a point where we urgently need to update a dependency, but it needs a recent setuptools.

When this is done, remove the pin of calver in the main gel repo.