libedit: 20170329-3.1 -> 20180525-3.1 (#41550)

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

- 0 of 0 passed binary check by having a zero exit code.
- 0 of 0 passed binary check by having the new version present in output.
- found 20180525-3.1 with grep in /nix/store/cjyizgchlbid5kq9qhgjm4bsn78i0kw7-libedit-20180525-3.1
- directory tree listing: https://gist.github.com/2cbcdedff99016d29804a14409a498fd
- du listing: https://gist.github.com/7e82fe655e6c31f0f57fef287fd71e54