remove LibreNews (unmaintained since 2021, website down) (#3796)

- https://librenews.io/ : HTTP 502
- 1b6bb93c96

README.md

@@ -345,7 +345,6 @@ _See also: [Comparison of CalDAV and CardDAV implementations - Wikipedia](https:
 - [Jami](https://jami.net/) - Free and universal communication platform which preserves the user's privacy and freedoms (formerly GNU Ring). ([Source Code](https://git.jami.net/savoirfairelinux/jami-project)) `GPL-3.0` `C++`
 - [KChat](https://github.com/php-kchat/kchat) - PHP Based Live Chat Application. `Apache-2.0` `PHP`
 - [LeapChat](https://www.leapchat.org/) - Ephemeral, encrypted, in-browser chat rooms. ([Source Code](https://github.com/cryptag/leapchat)) `AGPL-3.0` `Docker/Nodejs/Shell`
-- [LibreNews](https://librenews.io/) - Decentralized and secure breaking news notification system. ([Source Code](https://github.com/milesmcc/LibreNews-Server/)) `GPL-3.0` `Python`
 - [Live Helper Chat](https://livehelperchat.com/) - Live Support chat for your website. ([Source Code](https://github.com/LiveHelperChat/livehelperchat)) `Apache-2.0` `PHP`
 - [Mattermost](https://mattermost.org/) - Open-source, on-prem Slack-alternative. It can be integrated with Gitlab. ([Source Code](https://github.com/mattermost/mattermost-server)) `AGPL-3.0/Apache-2.0` `Go`
 - [MiAOU](https://miaou.dystroy.org/login) - Multi-room persistent chat server. ([Source Code](https://github.com/Canop/miaou)) `MIT` `Nodejs`