docs: update install-app-deps command usage example (#1729)

update install-app-deps usage example on Two package.json Structure docs to comply with module's warning message

docs/tutorials/Two package.json Structure.md

@@ -15,4 +15,4 @@ Why?
 
 Please see [Loading App Dependencies Manually](https://github.com/electron-userland/electron-builder/wiki/Loading-App-Dependencies-Manually) and [#379](https://github.com/electron-userland/electron-builder/issues/379#issuecomment-218503881).
 
-If you use the two-package.json project structure, you'll only have your `devDependencies` in your development `package.json` and your `dependencies` in your app `package.json`. To ensure your dependencies are always updated based on both files, simply add `"postinstall": "install-app-deps"` to your development `package.json`. This will basically automatically trigger an `npm install` within your app directory so you don't have to do this work every time you install/update your dependencies.
+If you use the two-package.json project structure, you'll only have your `devDependencies` in your development `package.json` and your `dependencies` in your app `package.json`. To ensure your dependencies are always updated based on both files, simply add `"postinstall": "electron-builder install-app-deps"` to your development `package.json`. This will basically automatically trigger an `npm install` within your app directory so you don't have to do this work every time you install/update your dependencies.