fix: double dashes in command with vite

[JensVanhulst]

Description of Problem

Double dashes in the scaffolding command with vite

npm init vite <proj-name> -- --template vue

Proposed Solution

npm init vite <proj-name> --template vue

Additional Information

[haoqunjiang]

Need to differentiate npm 6 and npm 7. See https://vitejs.dev/guide/#scaffolding-your-first-vite-project

[JensVanhulst]

@sodatea
Well it is not documented on the vue 3 docs as you can see below.
Isn't this confusing because if I'm on the vue site, I'm not going to follow the guide on vite ?

[haoqunjiang]

So I'm not closing this PR but requesting you to document both npm 6 & npm 7 behavior.
Otherwise it will confuse npm 7 users.

[JensVanhulst]

Should be fixed now.