Add DeepScan badge.

Author: ghengeveld

README.md

@@ -43,6 +43,9 @@
   <a href="https://www.codefactor.io/repository/github/ghengeveld/react-async">
     <img src="https://www.codefactor.io/repository/github/ghengeveld/react-async/badge" alt="code quality">
   </a>
+  <a href="https://deepscan.io/dashboard#view=project&tid=5147&pid=6925&bid=61474">
+    <img src="https://deepscan.io/api/teams/5147/projects/6925/branches/61474/badge/grade.svg" alt="DeepScan grade">
+  </a>
 </p>
 
 React component and hook for declarative promise resolution and data fetching. Makes it easy to handle every