Semi-automatic update generated by https://github.com/ryantm/nixpkgs-update tools. This update was made based on information from https://repology.org/metapackage/mpop/versions
* mpop: 1.2.6 -> 1.4.0 Update homepage and license. * mpop: 1.4.0 -> 1.4.1 https://marlam.de/mpop/news/mpop-1-4-1/ * mpop: don't use openssl per upstream's strong recommendation https://github.com/NixOS/nixpkgs/pull/51692#pullrequestreview-182938501