chore: remove the word "Preview" from vue 3 preset (#6310)

related to #6300

Author: tony19

packages/@vue/cli/lib/promptModules/vueVersion.js

@@ -17,7 +17,7 @@ module.exports = cli => {
         value: '2'
       },
       {
-        name: '3.x (Preview)',
+        name: '3.x',
         value: '3'
       }
     ],