Install manifest package before calling convert script

Author: millerds

package.json

@@ -18,7 +18,7 @@
   "scripts": {
     "build": "webpack --mode production",
     "build:dev": "webpack --mode development",
-    "convert-to-single-host": "node convertToSingleHost.js",
+    "convert-to-single-host": "npm install office-addin-manifest && node convertToSingleHost.js",
     "dev-server": "webpack serve --mode development",
     "lint": "office-addin-lint check",
     "lint:fix": "office-addin-lint fix",