notable changes:
- the project moved from `setup.py` to `pyproject`
- `setuptools-scm` was introduced as a build dependency
- `notmuch` is now used in the unittests
The nixpkgs-unstable channel's programs.sqlite was used to identify
packages producing exactly one binary, and these automatically added
to their package definitions wherever possible.
checkInputs used to be added to nativeBuildInputs. Now we have
nativeCheckInputs to do that instead. Doing this treewide change allows
to keep hashes identical to before the introduction of
nativeCheckInputs.
