README: fix link to tiptap

Signed-off-by: Adam Monsen <haircut@gmail.com>

README.md

@@ -13,7 +13,7 @@
 - **📝 Simple focused writing:** No distractions, only the formatting you need.
 - **🙋 Work together:** Share and collaborate with friends and colleagues, no matter if they use Nextcloud or not!
 - **💾 Open format:** Files are saved as [Markdown](https://en.wikipedia.org/wiki/Markdown), so you can edit them from any other text app too.
-- **✊ Strong foundation:** We use [🐈 tiptap](https://tiptap.scrumpy.io) which is based on [🦉 ProseMirror](https://prosemirror.net) – huge thanks to them!
+- **✊ Strong foundation:** We use [🐈 tiptap](https://tiptap.dev) which is based on [🦉 ProseMirror](https://prosemirror.net) – huge thanks to them!
 
 Nextcloud Text is the default text editor since Nextcloud 17. To start editing just open an existing markdown or plaintext file or create a new one.