gmic: 2.2.0 -> 2.2.1

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

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

These checks were done:

- built on NixOS
- ran `/nix/store/7d5z4y0x7ky7j3pk5pfswlbalv3wfg62-gmic-2.2.1/bin/gmic --version` and found version 2.2.1
- ran `/nix/store/7d5z4y0x7ky7j3pk5pfswlbalv3wfg62-gmic-2.2.1/bin/gmic version` and found version 2.2.1
- found 2.2.1 with grep in /nix/store/7d5z4y0x7ky7j3pk5pfswlbalv3wfg62-gmic-2.2.1
- directory tree listing: https://gist.github.com/1ee00489ce101a45c1c33912ab4c43c0