Removed Subrion entry as UNMAINTAINED (#2562)

Signed-off-by: Akashdeep Dhar <akashdeep.dhar@gmail.com>

README.md

@@ -561,7 +561,6 @@ _CMS are a practical way to setup a website with many features. CMS often come w
 - [SPIP](http://www.spip.net/fr) - Publication system for the Internet aimed at collaborative work, multilingual environments, and simplicity of use for web authors. ([Source Code](https://git.spip.net/)) `GPL-3.0` `PHP`
 - [Squidex](http://squidex.io) - Headless CMS, based on MongoDB, CQRS and Event Sourcing. ([Demo](http://cloud.squidex.io), [Source Code](https://github.com/Squidex/squidex)) `MIT` `.NET`
 - [Strapi](https://strapi.io/) - The most advanced open-source Content Management Framework (headless-CMS) to build powerful API with no effort. ([Source Code](https://github.com/strapi/strapi)) `MIT` `Nodejs`
-- [Subrion](http://www.subrion.org) - Subrion is a free open source content management system that allows you to build websites for any purpose. Yes, from blog to corporate mega portal. ([Demo](http://demos.subrion.com), [Source Code](https://github.com/intelliants/subrion)) `GPL-3.0` `PHP`
 - [Textpattern](http://textpattern.com/) - Flexible, elegant and easy-to-use CMS. ([Demo](http://textpattern.co/demo), [Source Code](https://github.com/textpattern/textpattern)) `GPL-2.0` `PHP`
 - [Typemill](https://typemill.net/) - Author-friendly flat-file-cms with a visual markdown editor based on vue.js. ([Source Code](https://github.com/typemill/typemill)) `MIT` `PHP`
 - [TYPO3](https://typo3.org/) - Powerful and advanced CMS with a large community. ([Source Code](https://github.com/TYPO3/TYPO3.CMS)) `GPL-2.0` `PHP`