cgal: 4.11.1 -> 4.12

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

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

These checks were done:

- built on NixOS
- ran ‘/nix/store/7py5j9ixfljnic4dr3ij97msnj0wahv6-cgal-4.12/bin/cgal_create_CMakeLists -h’ got 0 exit code
- ran ‘/nix/store/7py5j9ixfljnic4dr3ij97msnj0wahv6-cgal-4.12/bin/cgal_create_CMakeLists help’ got 0 exit code
- ran ‘/nix/store/7py5j9ixfljnic4dr3ij97msnj0wahv6-cgal-4.12/bin/cgal_create_cmake_script -h’ got 0 exit code
- ran ‘/nix/store/7py5j9ixfljnic4dr3ij97msnj0wahv6-cgal-4.12/bin/cgal_create_cmake_script --help’ got 0 exit code
- found 4.12 with grep in /nix/store/7py5j9ixfljnic4dr3ij97msnj0wahv6-cgal-4.12
- directory tree listing: https://gist.github.com/35067880611978f76a8e3f3adac7f12a