xonsh: 0.6.1 -> 0.6.3

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

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

These checks were done:

- built on NixOS
- ran ‘/nix/store/prjh0vgnnn80ba9im4j9minjivsa8bj4-xonsh-0.6.3/bin/.xonsh-wrapped -h’ got 0 exit code
- ran ‘/nix/store/prjh0vgnnn80ba9im4j9minjivsa8bj4-xonsh-0.6.3/bin/.xonsh-wrapped --help’ got 0 exit code
- ran ‘/nix/store/prjh0vgnnn80ba9im4j9minjivsa8bj4-xonsh-0.6.3/bin/.xonsh-wrapped help’ got 0 exit code
- ran ‘/nix/store/prjh0vgnnn80ba9im4j9minjivsa8bj4-xonsh-0.6.3/bin/.xonsh-wrapped -V’ and found version 0.6.3
- ran ‘/nix/store/prjh0vgnnn80ba9im4j9minjivsa8bj4-xonsh-0.6.3/bin/.xonsh-wrapped --version’ and found version 0.6.3
- ran ‘/nix/store/prjh0vgnnn80ba9im4j9minjivsa8bj4-xonsh-0.6.3/bin/xonsh -h’ got 0 exit code
- ran ‘/nix/store/prjh0vgnnn80ba9im4j9minjivsa8bj4-xonsh-0.6.3/bin/xonsh --help’ got 0 exit code
- ran ‘/nix/store/prjh0vgnnn80ba9im4j9minjivsa8bj4-xonsh-0.6.3/bin/xonsh help’ got 0 exit code
- ran ‘/nix/store/prjh0vgnnn80ba9im4j9minjivsa8bj4-xonsh-0.6.3/bin/xonsh -V’ and found version 0.6.3
- ran ‘/nix/store/prjh0vgnnn80ba9im4j9minjivsa8bj4-xonsh-0.6.3/bin/xonsh --version’ and found version 0.6.3
- found 0.6.3 with grep in /nix/store/prjh0vgnnn80ba9im4j9minjivsa8bj4-xonsh-0.6.3
- directory tree listing: https://gist.github.com/c4698aa16268961773b245a4b849a9f0
- du listing: https://gist.github.com/db7c65ccf5f4bf3c4457401c300d1862