git-cola: 3.0 -> 3.1

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

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

These checks were done:

- built on NixOS
- ran ‘/nix/store/vdgbmam99abv4kryg2bn31vkzdxk90cq-git-cola-3.1/bin/.git-cola-wrapped -h’ got 0 exit code
- ran ‘/nix/store/vdgbmam99abv4kryg2bn31vkzdxk90cq-git-cola-3.1/bin/.git-cola-wrapped --help’ got 0 exit code
- ran ‘/nix/store/vdgbmam99abv4kryg2bn31vkzdxk90cq-git-cola-3.1/bin/.git-cola-wrapped --version’ and found version 3.1
- ran ‘/nix/store/vdgbmam99abv4kryg2bn31vkzdxk90cq-git-cola-3.1/bin/.git-cola-wrapped version’ and found version 3.1
- ran ‘/nix/store/vdgbmam99abv4kryg2bn31vkzdxk90cq-git-cola-3.1/bin/git-cola -h’ got 0 exit code
- ran ‘/nix/store/vdgbmam99abv4kryg2bn31vkzdxk90cq-git-cola-3.1/bin/git-cola --help’ got 0 exit code
- ran ‘/nix/store/vdgbmam99abv4kryg2bn31vkzdxk90cq-git-cola-3.1/bin/git-cola --version’ and found version 3.1
- ran ‘/nix/store/vdgbmam99abv4kryg2bn31vkzdxk90cq-git-cola-3.1/bin/git-cola version’ and found version 3.1
- ran ‘/nix/store/vdgbmam99abv4kryg2bn31vkzdxk90cq-git-cola-3.1/bin/.git-dag-wrapped -h’ got 0 exit code
- ran ‘/nix/store/vdgbmam99abv4kryg2bn31vkzdxk90cq-git-cola-3.1/bin/.git-dag-wrapped --help’ got 0 exit code
- ran ‘/nix/store/vdgbmam99abv4kryg2bn31vkzdxk90cq-git-cola-3.1/bin/.git-dag-wrapped --version’ and found version 3.1
- ran ‘/nix/store/vdgbmam99abv4kryg2bn31vkzdxk90cq-git-cola-3.1/bin/git-dag -h’ got 0 exit code
- ran ‘/nix/store/vdgbmam99abv4kryg2bn31vkzdxk90cq-git-cola-3.1/bin/git-dag --help’ got 0 exit code
- ran ‘/nix/store/vdgbmam99abv4kryg2bn31vkzdxk90cq-git-cola-3.1/bin/git-dag --version’ and found version 3.1
- found 3.1 with grep in /nix/store/vdgbmam99abv4kryg2bn31vkzdxk90cq-git-cola-3.1
- directory tree listing: https://gist.github.com/af016e8541c2ac80ef4e4e16a00bc0de