This is the first version using setuptools-scm. Because we don't keep
enough git metadata to determine the version, we use
SETUPTOOLS_SCM_PRETEND_VERSION instead.
https://github.com/NixOS/nixpkgs/issues/41136
Because enaml 0.13.0 doesn't work with atom 0.7.0,
which is already in nixpkgs. 0.14.0 works again.
(`enaml/layout/strength_member.py` was calling `__init__`
on `Value` with 3 positional parameters, but atom 0.7.0
changed them to named ones, and enaml 0.14.0 is updated
accordingly).
