lightdm_gtk_greeter: 2.0.4 -> 2.0.5

Semi-automatic update generated by https://github.com/ryantm/nix-update tools. These checks were done:

- built on NixOS
/tmp/tmp.Ened4Ypstm /home/ryantm/.cache/nixpkgs
/home/ryantm/.cache/nixpkgs
- Warning: no binary found that responded to help or version flags. (This warning appears even if the package isn't expected to have binaries.)
- found 2.0.5 with grep in /nix/store/w1whi2qkvm97pbk0mjigs7xhnd2vgczx-lightdm-gtk-greeter-2.0.5
- directory tree listing: https://gist.github.com/7fa4fc4e3d6e3d17e75f94d3a9798382