fix($plugin-google-analytics): duplicate tracking of first page (fix #2017) (#2039)

Author: ajitzero

packages/@vuepress/plugin-google-analytics/enhanceAppFile.js

@@ -18,7 +18,6 @@ export default ({ router }) => {
 
     ga('create', GA_ID, 'auto')
     ga('set', 'anonymizeIp', true)
-    ga('send', 'pageview')
 
     router.afterEach(function (to) {
       ga('set', 'page', to.fullPath)