mdds: 1.2.2 -> 1.3.1

Semi-automatic update generated by https://github.com/ryantm/nix-update tools. 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 1.3.1 with grep in /nix/store/1jh7ran6gm77rksnm74kix37b44b1ni9-mdds-1.3.1
- directory tree listing: https://gist.github.com/bd00a4a5fa8495574a863ebf42d43a9a