Add yarn install state

config/routines/example.config.js

@@ -152,6 +152,13 @@ const example_routine = {
             source: 'https://static.garrettmills.dev/assets/flitter/flitter_f.png',
             path: '/tmp/flitter_f.png',
         },
+        {
+            // State: the packages for the given path are installed via Yarn
+            type: 'node.yarn.installed',
+            host: 'localhost',
+            path: '/home/user/path/to/project',
+            force: true, // default: false
+        },
     ],
 }