lynis: 2.6.3 -> 2.6.4

Semi-automatic update generated by https://github.com/ryantm/nixpkgs-update tools.

This update was made based on information from https://repology.org/metapackage/lynis/versions.

These checks were done:

- built on NixOS
- ran ‘/nix/store/6z5szmm4m9jix1062zrp1m556g75lbwf-lynis-2.6.4/bin/lynis -V’ and found version 2.6.4
- ran ‘/nix/store/6z5szmm4m9jix1062zrp1m556g75lbwf-lynis-2.6.4/bin/lynis --version’ and found version 2.6.4
- ran ‘/nix/store/6z5szmm4m9jix1062zrp1m556g75lbwf-lynis-2.6.4/bin/.lynis-wrapped -V’ and found version 2.6.4
- ran ‘/nix/store/6z5szmm4m9jix1062zrp1m556g75lbwf-lynis-2.6.4/bin/.lynis-wrapped --version’ and found version 2.6.4
- found 2.6.4 with grep in /nix/store/6z5szmm4m9jix1062zrp1m556g75lbwf-lynis-2.6.4
- directory tree listing: https://gist.github.com/bb3a08cde57013b3af4f2511af3cc77c