glew: 2.0.0 -> 2.1.0

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

This update was made based on information from https://repology.org/metapackage/glew/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 2.1.0 with grep in /nix/store/r6kh84dxq1pi99hcc2dip060kwbg5164-glew-2.1.0-bin
- directory tree listing: https://gist.github.com/5a1de7b9365c14af6aca6f9b9c76b6c1