Remove Taskboard (unmaintained since 2021) (#3809)

- WARNING:awesome_lint.py: TaskBoard: last updated -715 days, 23:21:55.812771 ago, older than 365 days
- ref. https://github.com/awesome-selfhosted/awesome-selfhosted/issues/3558
- https://github.com/kiswa/TaskBoard#readme: MAINTAINERS WANTED

README.md

@@ -1969,7 +1969,6 @@ _Related: [Software Development - Project Management](#software-development---pr
 - [Planka](https://planka.app/) - Open source Trello alternative. ([Demo](https://plankanban.github.io/planka/#/), [Source Code](https://github.com/plankanban/planka)) `AGPL-3.0` `Nodejs`
 - [Restyaboard](https://github.com/RestyaPlatform/board/) - Open source Trello-like kanban board. `OSL-3.0` `PHP`
 - [Task Keeper](https://github.com/nymanjens/piga) - List editor for power users, backed by a self-hosted server. `Apache-2.0` `Scala`
-- [TaskBoard](https://taskboard.matthewross.me/) - Kanban-inspired app for keeping track of things that need to get done. ([Demo](https://taskboard.matthewross.me/demo.html), [Source Code](https://github.com/kiswa/TaskBoard)) `MIT` `PHP`
 - [Tasks](https://github.com/m1guelpf/tasks) - Simple tasks and notes manager written in PHP, jQuery and Bootstrap using a custom flat file database. `MPL-2.0` `PHP`
 - [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`