doit: 0.31.0 -> 0.31.1

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

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

These checks were done:

- built on NixOS
- ran `/nix/store/xgn48w19lgr8xnijgqcx91389b5hldv2-doit-0.31.1/bin/.doit-wrapped --help` got 0 exit code
- ran `/nix/store/xgn48w19lgr8xnijgqcx91389b5hldv2-doit-0.31.1/bin/.doit-wrapped help` got 0 exit code
- ran `/nix/store/xgn48w19lgr8xnijgqcx91389b5hldv2-doit-0.31.1/bin/.doit-wrapped --version` and found version 0.31.1
- ran `/nix/store/xgn48w19lgr8xnijgqcx91389b5hldv2-doit-0.31.1/bin/doit --help` got 0 exit code
- ran `/nix/store/xgn48w19lgr8xnijgqcx91389b5hldv2-doit-0.31.1/bin/doit help` got 0 exit code
- ran `/nix/store/xgn48w19lgr8xnijgqcx91389b5hldv2-doit-0.31.1/bin/doit --version` and found version 0.31.1
- found 0.31.1 with grep in /nix/store/xgn48w19lgr8xnijgqcx91389b5hldv2-doit-0.31.1
- directory tree listing: https://gist.github.com/a0ba66d49e0c01c3003ca50e9ad705a0