remove dead link/alltube homepage

- the official instance hosted on heroku was retired/heroku free plan EOL
- https://github.com/Rudloff/alltube/issues/422
- ref. https://github.com/awesome-selfhosted/awesome-selfhosted/issues/2266

README.md

@@ -156,7 +156,7 @@ _Related: [Internet of Things (IoT)](#internet-of-things-iot)_
 - [Actionsflow](https://actionsflow.github.io/docs/) `⚠` - The free Zapier/IFTTT alternative for developers to automate your workflows based on Github actions. ([Source Code](https://github.com/actionsflow/actionsflow)) `MIT` `Docker/Nodejs`
 - [Activepieces](https://www.activepieces.com) - No-code business automation tool like Zapier or Tray. For example, you can send a Slack notification for each new Trello card. ([Demo](https://demo.activepieces.com), [Source Code](https://www.github.com/activepieces/activepieces)) `MIT` `Typescript`
 - [ActiveWorkflow](https://github.com/automaticmode/active_workflow) - An intelligent process and workflow automation platform based on software agents. `MIT` `Ruby`
-- [Alltube](https://www.alltubedownload.net) - Web interface for [youtube-dl](https://github.com/ytdl-org/youtube-dl), a program to download videos and audio from [more than 100 websites](https://ytdl-org.github.io/youtube-dl/supportedsites.html). ([Source Code](https://github.com/Rudloff/alltube)) `GPL-3.0` `PHP`
+- [Alltube](https://github.com/Rudloff/alltube) - Web GUI for youtube-dl, a program to download videos and audio from more than 100 websites. `GPL-3.0` `PHP`
 - [AmIUnique](https://amiunique.org/) - Learn how identifiable you are on the Internet (browser fingerprinting tool). ([Source Code](https://github.com/DIVERSIFY-project/amiunique)) `MIT` `Java`
 - [Automatisch](https://automatisch.io) - Business automation tool that lets you connect different services like Twitter, Slack, and more to automate your business processes (Open source Zapier alternative). ([Source Code](https://github.com/automatisch/automatisch)) `AGPL-3.0` `Docker`
 - [Baserow](https://baserow.io/) - Open source online database tool and Airtable alternative. Create your own database without technical experience. ([Source Code](https://gitlab.com/bramw/baserow)) `MIT` `Python/Nodejs`