live555: 2019.08.16 -> 2019.10.20 (#69656)

* live555: 2019.08.16 -> 2019.09.18

Semi-automatic update generated by
https://github.com/ryantm/nixpkgs-update tools. This update was made
based on information from
https://repology.org/metapackage/live555/versions

* live555: 2019.09.18 -> 2019.10.20