gitAndTools.git-open: 1.3.1 -> 2.0.0

Semi-automatic update generated by https://github.com/ryantm/nix-update tools. 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 2.0.0 with grep in /nix/store/bl1bdnjxn6k22is2w6qvdjl7kvhzjv2s-git-open-2.0.0
- directory tree listing: https://gist.github.com/7c26064e56c054ea6ba2b4d9162267cd