imagemagick7: 7.0.7-22 -> 7.0.7-27

Semi-automatic update generated by https://github.com/ryantm/nix-update tools. These checks were done:

- built on NixOS
/tmp/tmp.quAyurRyhL /home/ryantm/.cache/nixpkgs
/home/ryantm/.cache/nixpkgs
- ran `/nix/store/8n4a2v0wfmzlk9n2bdv919ybg17bai8c-imagemagick-7.0.7-27/bin/magick -h` got 0 exit code
- ran `/nix/store/8n4a2v0wfmzlk9n2bdv919ybg17bai8c-imagemagick-7.0.7-27/bin/magick --help` got 0 exit code
- ran `/nix/store/8n4a2v0wfmzlk9n2bdv919ybg17bai8c-imagemagick-7.0.7-27/bin/magick help` got 0 exit code
- ran `/nix/store/8n4a2v0wfmzlk9n2bdv919ybg17bai8c-imagemagick-7.0.7-27/bin/magick --version` and found version 7.0.7-27
- found 7.0.7-27 with grep in /nix/store/8n4a2v0wfmzlk9n2bdv919ybg17bai8c-imagemagick-7.0.7-27
- directory tree listing: https://gist.github.com/4c89cc9d32b6739922d277619629d087