riot-web: 0.14.1 -> 0.14.2

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

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

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 0.14.2 with grep in /nix/store/zglwk185bfl8x2dmkqpl51801rk58gvi-riot-web-0.14.2
- directory tree listing: https://gist.github.com/eae072ce5bb48e5e8b59f7e04caf5b0d