Update all references of the new command in docs

Signed-off-by: Min Kim <minkimcello@gmail.com>

docs/tutorials/quickstart-app-plugin.md

@@ -30,7 +30,7 @@ title: Adding Custom Plugin to Existing Monorepo App
 # The Skeleton Plugin
 
 1. Start by using the built-in creator. From the terminal and root of your
-   project run: `yarn new --select plugin`
+   project run: `yarn new` and select `frontend-plugin`.
 1. Enter a plugin ID. I used `github-playground`
 1. When the process finishes, let's start the backend:
    `yarn --cwd packages/backend start`