remove linkding demo link

- website unreachable over IPv4

README.md

@@ -262,7 +262,7 @@ Software which allows users to add, annotate, edit, and share [bookmarks](https:
 - [golinks](https://git.mills.io/prologic/golinks) - Web application that allows you to create smart bookmarks, commands and aliases by pointing your web browser's default search engine at a running instance. Similar to bunny1 or yubnub. ([Demo](https://search.mills.io)) `MIT` `Go`
 - [Hackershare](https://github.com/hackershare/hackershare) - Social bookmarks website for hackers. ([Demo](https://hackershare.dev/en)) `MIT` `Ruby`
 - [LinkAce](https://www.linkace.org/) - A bookmark archive with automatic backups to the Internet Archive, link monitoring, and a full REST API. Installation is done via Docker, or as a simple PHP application. ([Demo](https://demo.linkace.org/guest/links), [Source Code](https://github.com/Kovah/LinkAce/)) `GPL-3.0` `PHP`
-- [linkding](https://github.com/sissbruecker/linkding) - Minimal bookmark management with a fast and clean UI. Simple installation through Docker and can run on your Raspberry Pi. ([Demo](https://demo.linkding.link/bookmarks)) `MIT` `Docker/Python/Nodejs`
+- [linkding](https://github.com/sissbruecker/linkding) - Minimal bookmark management with a fast and clean UI. Simple installation through Docker and can run on your Raspberry Pi. `MIT` `Docker/Python/Nodejs`
 - [LinkWarden](https://github.com/Daniel31x13/link-warden) - A self-hosted bookmark + archive manager to store your useful links. ([Demo](https://linkwarden.netlify.app/)) `MIT` `Docker/Nodejs`
 - [NeonLink](https://github.com/AlexSciFier/neonlink) - Self-hosted bookmark service with unique design and simple installation with Docker. `MIT` `Docker`
 - [Pinry](https://docs.getpinry.com/) - The tiling image board system for people who want to save, tag, and share images, videos, and webpages. ([Demo](https://pin.37soloist.com/), [Source Code](https://github.com/pinry/pinry)) `BSD-2-Clause` `Python`