docs: add ga plugin

Author: Simpleyyt

docs/index.html

@@ -48,6 +48,7 @@
   <script src="//cdn.jsdelivr.net/npm/docsify-copy-code/dist/docsify-copy-code.min.js"></script>
   <script src="//cdn.jsdelivr.net/npm/docsify/lib/plugins/emoji.min.js"></script>
   <script src="//unpkg.com/docsify-pagination/dist/docsify-pagination.min.js"></script>
+  <script src="//cdn.jsdelivr.net/npm/docsify/lib/plugins/ga.min.js"></script>
 </body>
 
 </html>