README: mention Matrix channel

Author: poettering

README.md

@@ -34,6 +34,6 @@ Please see our [Contribution Guidelines](docs/CONTRIBUTING.md) for more informat
 
 When preparing patches for systemd, please follow our [Coding Style Guidelines](docs/CODING_STYLE.md).
 
-If you are looking for support, please contact our [mailing list](https://lists.freedesktop.org/mailman/listinfo/systemd-devel) or join our [IRC channel](irc://irc.libera.chat/%23systemd).
+If you are looking for support, please contact our [mailing list](https://lists.freedesktop.org/mailman/listinfo/systemd-devel), join our [IRC channel](irc://irc.libera.chat/%23systemd) or [Matrix channel](https://matrix.to/#/#systemd-project:matrix.org)
 
 Stable branches with backported patches are available in the [stable repo](https://github.com/systemd/systemd-stable).