matio: 1.5.11 -> 1.5.12

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

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

These checks were done:

- built on NixOS
- ran `/nix/store/g0zdli6b3hzmnwdzyq1jblh89kqvxaqw-matio-1.5.12/bin/matdump --help` got 0 exit code
- ran `/nix/store/g0zdli6b3hzmnwdzyq1jblh89kqvxaqw-matio-1.5.12/bin/matdump -V` and found version 1.5.12
- ran `/nix/store/g0zdli6b3hzmnwdzyq1jblh89kqvxaqw-matio-1.5.12/bin/matdump --version` and found version 1.5.12
- found 1.5.12 with grep in /nix/store/g0zdli6b3hzmnwdzyq1jblh89kqvxaqw-matio-1.5.12
- directory tree listing: https://gist.github.com/d5648482494f82e4d49cc3aea608b4fa