miniupnpd: 2.1 -> 2.1.20180706 (#43186)

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

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

These checks were done:

- built on NixOS
- Warning: no invocation of /nix/store/qnqg5q28if28n82q1p5f2mq1amssl29q-miniupnpd-2.1.20180706/bin/miniupnpd had a zero exit code or showed the expected version
- 0 of 1 passed binary check by having a zero exit code.
- 0 of 1 passed binary check by having the new version present in output.
- directory tree listing: https://gist.github.com/2d95ffcb0003f1ba64f195d8ebbf3e0d
- du listing: https://gist.github.com/67d8cb75611b4683d6596e76fe599f50