* Update to the latest upstream version of pass-secret-service that includes
systemd service files.
* Add patch to fix use of a function that has been removed from the Python
Cryptography library in NixOS 22.05
* Install systemd service files in the Nix package.
* Add NixOS test to ensure the D-Bus API activates the service unit.
* Add myself as a maintainer to the package and NixOS test.
* Use checkTarget instead of equivalent custom checkPhase.
