feat: add sponsor badge

Author: TomerAberbach

readme.md

@@ -9,6 +9,9 @@
   <a href="https://github.com/TomerAberbach/src2img/actions">
     <img src="https://github.com/TomerAberbach/src2img/workflows/CI/badge.svg" alt="CI" />
   </a>
+  <a href="https://github.com/sponsors/TomerAberbach">
+    <img src="https://img.shields.io/static/v1?label=Sponsor&message=%E2%9D%A4&logo=GitHub&color=%23fe8e86" alt="Sponsor">
+  </a>
 </div>
 
 <div align="center">