fping: 3.16 -> 4.0

Semi-automatic update. These checks were done:

- built on NixOS
- 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 4.0 with grep in /nix/store/mcwq9l7zxi30ksdmlfj5vlcw98dv08ny-fping-4.0
- found 4.0 in filename of file in /nix/store/mcwq9l7zxi30ksdmlfj5vlcw98dv08ny-fping-4.0