armadillo: 8.500.1 -> 8.600.0

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

This update was made based on information from https://repology.org/metapackage/armadillo/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 8.600.0 with grep in /nix/store/m4l2zgjz09q33vv7k1gfj5h5qai41zz5-armadillo-8.600.0
- directory tree listing: https://gist.github.com/1453f46d5d1e8d2711fee7764e49fc8b
- du listing: https://gist.github.com/843d38178389290c409688879c45f3b0