znc: 1.6.6 -> 1.7.0 (#40055)

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

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

These checks were done:

- built on NixOS
- ran ‘/nix/store/kkf4gxgjxcq0j8cm6yv5mnv6b8klbgrf-znc-1.7.0/bin/znc -h’ got 0 exit code
- ran ‘/nix/store/kkf4gxgjxcq0j8cm6yv5mnv6b8klbgrf-znc-1.7.0/bin/znc --help’ got 0 exit code
- found 1.7.0 with grep in /nix/store/kkf4gxgjxcq0j8cm6yv5mnv6b8klbgrf-znc-1.7.0
- directory tree listing: https://gist.github.com/766f104f22de520d85cc6b31c46cd5db