libedit: 20160903-3.1 -> 20170329-3.1

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

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

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 20170329-3.1 with grep in /nix/store/ypc37byfr7pqh02h1wwmlxn0qxfqm1rc-libedit-20170329-3.1
- directory tree listing: https://gist.github.com/f77554015e717beead00f8cfe7d57d8e