Rremove todo (unmaintained since November 2022, outdated base image) (#4064)

- https://git.mills.io/prologic/todo/commits/branch/master
- uses outdated/vulnerable alpine 3.17.0 base image
- ref. #3558

README.md

@@ -1992,7 +1992,6 @@ _Related: [Software Development - Project Management](#software-development---pr
 - [Task Keeper](https://github.com/nymanjens/piga) - List editor for power users, backed by a self-hosted server. `Apache-2.0` `Scala`
 - [Tasks.md](https://github.com/BaldissaraMatheus/Tasks.md) - A self-hosted, file based task management board that supports Markdown syntax. `MIT` `Docker`
 - [Taskwarrior](https://taskwarrior.org/) - Taskwarrior is Free and Open Source Software that manages your TODO list from your command line. It is flexible, fast, efficient, and unobtrusive. It does its job then gets out of your way. ([Source Code](https://taskwarrior.org/download/#git)) `MIT` `C++`
-- [todo](https://git.mills.io/prologic/todo) - Simple todo list manager. ([Demo](https://todo.mills.io)) `MIT` `Go`
 - [Tracks](https://www.getontracks.org/) - Web-based application to help you implement David Allen’s [Getting Things Done™](https://en.wikipedia.org/wiki/Getting_Things_Done) methodology. ([Source Code](https://github.com/TracksApp/tracks)) `GPL-2.0` `Ruby`
 - [Vikunja](https://vikunja.io/) - The to-do app to organize your life. ([Demo](https://try.vikunja.io/login), [Source Code](https://kolaente.dev/vikunja/)) `GPL-3.0` `Go`
 - [Wekan](https://wekan.github.io/) - Open-source Trello-like kanban. ([Source Code](https://github.com/wekan/wekan)) `MIT` `Nodejs`