libmediainfo: 18.03 -> 18.03.1

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

This update was made based on information from https://repology.org/metapackage/libmediainfo/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 18.03.1 with grep in /nix/store/6q9709wh9dins0xbp9cp9yc9w1vj29ja-libmediainfo-18.03.1
- directory tree listing: https://gist.github.com/433043833de962c7cbb5237224bdc026