chore: update sponsor link

Author: yyx990803

README.md

@@ -122,7 +122,7 @@ Funds donated via Patreon goes directly to support Evan You's full-time work on
         </a>
       </td>
       <td align="center" valign="middle">
-        <a href="https://themeforest.net/item/clear-bootstrap-vuejs-admin-template/19339739?ref=jyostna&utm_source=vuejs&utm_campaign=vuejs_patreon&clickthrough_id=1113830525&redirect_back=true" target="_blank">
+        <a href="https://themeforest.net/item/clear-bootstrap-vuejs-admin-template/19339739?ref=jyostna&utm_source=vuejs.org&utm_campaign=vuejs_patreon" target="_blank">
           <img width="150px" src="https://raw.githubusercontent.com/vuejs/vuejs.org/master/themes/vue/source/images/vuejsadmin.png">
         </a>
       </td>