aadded google site verification tag

Author: Dipak Sarkar

docs/.vuepress/config.js

@@ -19,6 +19,7 @@ module.exports = {
     ['meta', { name: 'theme-color', content: '#3eaf7c' }],
     ['meta', { name: 'apple-mobile-web-app-capable', content: 'yes' }],
     ['meta', { name: 'apple-mobile-web-app-status-bar-style', content: 'black' }]
+    ['meta', { name: 'google-site-verification', content: 'Tf6UVeu-ZmZtGqB5tdcYymZ79101gyGKcpzqwWhDb1U' }]
   ],
 
   /**