remove radium demo link (error 503)

- ref. https://github.com/awesome-selfhosted/awesome-selfhosted/issues/2266

README.md

@@ -1256,7 +1256,7 @@ _See also: [List of streaming media systems - Wikipedia](https://en.wikipedia.or
 - [OvenMediaEngine](https://ovenmediaengine.com) - OvenMediaEngine is a selfhostable Open-Source Streaming Server with Sub-Second Latency. ([Demo](https://demo.ovenplayer.com), [Source Code](https://github.com/AirenSoft/OvenMediaEngine)) `GPL-3.0` `C++`
 - [Owncast](https://github.com/owncast/owncast) - Owncast is an open source, self-hosted, decentralized, single user live video streaming and chat server for running your own live streams similar in style to the large mainstream options. `MIT` `Go`
 - [PeerTube](https://joinpeertube.org/en/) - Decentralized video streaming platform using P2P (BitTorrent) directly in the web browser. ([Source Code](https://github.com/Chocobozzz/PeerTube)) `AGPL-3.0` `Nodejs`
-- [Radium](https://github.com/Zibbp/Radium) - Synced stream and video playback with VOD capabilities utilizing HLS. Developed for movie nights but has many use cases. ([Demo](https://radium-demo.herokuapp.com)) `MIT` `Nodejs/Docker`
+- [Radium](https://github.com/Zibbp/Radium) - Synced stream and video playback with VOD capabilities utilizing HLS. Developed for movie nights but has many use cases. `MIT` `Nodejs/Docker`
 - [Rapidbay](https://github.com/hauxir/rapidbay/) - Self-hosted torrent videostreaming service/torrent client that allows searching and playing videos from torrents in the browser or from a Chromecast/AppleTV/Smart TV. `MIT` `Python/Docker`
 - [Restreamer](https://datarhei.github.io/restreamer/) - Restreamer allows you to do h.264 real-time video streaming on your website without a streaming provider. ([Source Code](https://github.com/datarhei/restreamer)) `Apache-2.0` `Nodejs/Docker`
 - [ShinobiCE](https://gitlab.com/Shinobi-Systems/ShinobiCE) - Open Source CCTV software written in Node with both IP and local camera support. `AGPL-3.0/GPL-3.0` `Nodejs`