Update README.md

Signed-off-by: David Lapshin <[email protected]>

Author: daudix

README.md

@@ -1,6 +1,8 @@
 > [!IMPORTANT]
+> Gradience has been archived as of July 29, 2024. See the [blog post](https://daudix.one/blog/archiving-gradience/) for some information on the rationale behind this decision.
+
+> [!NOTE]
 > Gradience is looking for a maintainer(s)! if you know Python and GTK4/Libadwaita and willing to work on it, chip in on [Matrix](https://matrix.to/#/#Gradience:matrix.org) and [Discord](https://discord.com/invite/4njFDtfGEZ).
->
 
 <h1 align="center">
   <img src="data/icons/hicolor/scalable/apps/com.github.GradienceTeam.Gradience.svg" alt="Gradience" width="192" height="192"/>