Add validate

Author: Bre77

packages/homey/package.json

@@ -7,7 +7,8 @@
     "tsc": "tsc",
     "build": "tsdown",
     "lint": "eslint --ext .js,.ts --ignore-path .gitignore .",
-    "dev": "homey app run"
+    "dev": "homey app run",
+    "validate": "homey app validate"
   },
   "devDependencies": {
     "@teslemetry/api": "workspace:*",