Revert "Removed Tox entry as UNUPDATED (#2566)"

This reverts commit 6180c555c3.

README.md

@@ -310,6 +310,7 @@ _See also: [Comparison of CalDAV and CardDAV implementations - Wikipedia](https:
 - [Syndie](https://syndie.de) - Syndie is a libre system for operating distributed forums. `CC0-1.0` `Java`
 - [TextBelt](https://github.com/typpo/textbelt) `⚠` - Outgoing SMS API that uses carrier-specific gateways to deliver your text messages for free, and without ads. `MIT` `Javascript`
 - [Tinode](https://github.com/tinode) - Instant messaging platform. Backend in Go. Clients: Swift iOS, Java Android, JS webapp, scriptable command line; chatbots. ([Demo](https://sandbox.tinode.co/), [Source Code](https://github.com/tinode/chat), [Clients](https://github.com/tinode/webapp)) `GPL-3.0` `Go`
+- [Tox](https://tox.chat/) - Distributed, secure messenger with audio and video chat capabilities. ([Source Code](https://github.com/irungentoo/toxcore)) `GPL-3.0` `C`
 - [Tuber](https://blog.trailofbits.com/2015/12/15/self-hosted-video-chat-with-tuber/) - Peer-to-peer video chat that works. ([Source Code](https://github.com/trailofbits/tubertc)) `MIT` `Javascript`
 - [WBO](https://github.com/lovasoa/whitebophir#wbo) -  A web Whiteboard to collaborate in real-time on schemas, drawings, and notes. ([Demo](https://wbo.ophir.dev/)) `AGPL-3.0` `Nodejs/Docker`
 - [ZeroNet](https://zeronet.io/) `⚠` - Open, free, and uncensorable websites, using Bitcoin cryptography and BitTorrent network. ([Source Code](https://github.com/HelloZeroNet/ZeroNet)) `GPL-2.0` `Python`