Merge pull request #63 from PrivateStorageio/54.expose-voucher-state

docs/source/interface.rst

src/_zkapauthorizer/controller.py

src/_zkapauthorizer/model.py

src/_zkapauthorizer/resource.py

src/_zkapauthorizer/tests/strategies.py

src/_zkapauthorizer/tests/test_client_resource.py

src/_zkapauthorizer/tests/test_controller.py

src/_zkapauthorizer/tests/test_model.py

zkapauthorizer.nix