vue*: update outdated pages to latest Vue.js version.

Update the examples of the following pages to the latest Vue.js version:

 - vue.md
 - vue-init.md
 - vue-build.md
 - vue-serve.md

pages/common/vue-serve.md

@@ -0,0 +1,8 @@
+# vue serve
+
+> A subcommand provided by `@vue/cli` and `@vue/cli-service-global` that enables quick prototyping.
+> More information: <https://cli.vuejs.org/guide/prototyping.html>.
+
+- Serve a `.js` or `.vue` file in development mode with zero config:
+
+`vue serve {{filename}}`