chore: add link to sponsor svgs [ci skip]

Author: yyx990803

BACKERS.md

@@ -3,5 +3,7 @@
 Vue.js is an MIT-licensed open source project with its ongoing development made possible entirely by the support of the awesome sponsors and backers listed in this file. If you'd like to join them, please consider [ sponsor Vue's development](https://staging.vuejs.org/sponsor/).
 
 <p align="center">
-  <img src="https://sponsors.vuejs.org/backers.svg">
+  <a target="_blank" href="https://sponsors.vuejs.org/backers.svg">
+    <img alt="sponsors" src="https://sponsors.vuejs.org/backers.svg">
+  </a>
 </p>

README.md

@@ -26,5 +26,7 @@ Also note: Vue 3 does not support IE11 ([RFC](https://github.com/vuejs/rfcs/blob
 Vue.js is an MIT-licensed open source project with its ongoing development made possible entirely by the support of these awesome [backers](https://github.com/vuejs/core/blob/main/BACKERS.md). If you'd like to join them, please consider [ sponsor Vue's development](https://staging.vuejs.org/sponsor/).
 
 <p align="center">
-  <img src="https://sponsors.vuejs.org/sponsors.svg">
+  <a target="_blank" href="https://sponsors.vuejs.org/sponsors.svg">
+    <img alt="sponsors" src="https://sponsors.vuejs.org/sponsors.svg">
+  </a>
 </p>