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

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

These checks were done:

- built on NixOS
- Warning: no invocation of /nix/store/rzhnqdk6w2pmkg770dp4d4b5dfhg6dxc-libnfs-3.0.0/bin/nfs-cat had a zero exit code or showed the expected version
- Warning: no invocation of /nix/store/rzhnqdk6w2pmkg770dp4d4b5dfhg6dxc-libnfs-3.0.0/bin/nfs-ls had a zero exit code or showed the expected version
- /nix/store/rzhnqdk6w2pmkg770dp4d4b5dfhg6dxc-libnfs-3.0.0/bin/nfs-cp passed the binary check.
- 1 of 3 passed binary check by having a zero exit code.
- 0 of 3 passed binary check by having the new version present in output.
- found 3.0.0 with grep in /nix/store/rzhnqdk6w2pmkg770dp4d4b5dfhg6dxc-libnfs-3.0.0
- directory tree listing: https://gist.github.com/41f09d1c597fdac38e45fb2ab6bec655
- du listing: https://gist.github.com/00ddd65dc42da40cbedb9ae1fe041f73

libnfs: 2.0.0 -> 3.0.0