revert: feat(index): support automatically install for standalone

This reverts commit ada2673.

Author: kazupon

src/index.js

@@ -2,13 +2,13 @@ import extend from './extend'
 
 
 /**
- * install
+ * plugin
  *
  * @param {Object} Vue
  * @param {Object} opts
  */
 
-export default function install (Vue, opts = { lang: 'en', locales: {} }) {
+export default function (Vue, opts = { lang: 'en', locales: {} }) {
   defineConfig(Vue.config, opts.lang)
   extend(Vue, opts.locales)
 }
@@ -30,12 +30,3 @@ function defineConfig (config, lang) {
     set: (val) => { lang = val }
   })
 }
-
-
-/**
- * install automaticlly 
- */
-
-if (typeof window !== 'undefined' && window.Vue) {
-  window.Vue.use(install)
-}