libcap_ng: 0.7.8 -> 0.7.9

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

- built on NixOS
- ran `/nix/store/s6hxbgihfzp3phh3904idpw3jpn1k371-libcap-ng-0.7.9/bin/captest -h` got 0 exit code
- ran `/nix/store/s6hxbgihfzp3phh3904idpw3jpn1k371-libcap-ng-0.7.9/bin/captest --help` got 0 exit code
- ran `/nix/store/s6hxbgihfzp3phh3904idpw3jpn1k371-libcap-ng-0.7.9/bin/captest help` got 0 exit code
- found 0.7.9 with grep in /nix/store/s6hxbgihfzp3phh3904idpw3jpn1k371-libcap-ng-0.7.9
- directory tree listing: https://gist.github.com/eec1818588ca8e5fe720bfe3febec73b