Add Landscape to README.md

Added Landscape Docs as a participating project

Author: YanisaHS

README.md

@@ -24,6 +24,7 @@ The first words of an issue's title will typically indicate the project it invol
 - [Juju](https://juju.is/docs):  open source orchestration engine
 - [Canonical Kubernetes](https://ubuntu.com/kubernetes/docs): the reference platform for Kubernetes on all major public clouds
 - [LXD](https://documentation.ubuntu.com/lxd/en/latest/): open source container and VM management at any scale
+- [Landscape](https://ubuntu.com/landscape/docs): Ubuntu systems management, monitoring and administration platform
 - [Launchpad](https://documentation.ubuntu.com/launchpad/en/latest/): software development lifecycle and collaboration platform
 - [MAAS](https://maas.io/docs): bare metal cloud with on-demand servers
 - [Our Sphinx and RST starter pack](https://github.com/canonical/sphinx-docs-starter-pack): our open source template for building modern documentation