Use cdnjs for playground to reduce serer costs.

Author: ricmoo

playground/index.html

@@ -77,7 +77,10 @@
         </div>
       </div>
     </div>
+    <script src="https://cdnjs.cloudflare.com/ajax/libs/ethers/5.6.4/ethers.umd.min.js" integrity="sha512-EKCEAWajhazrbxxXV+UKphn1Vl1MhIbZxCy5kPVzVrTRKYJ96r7QtPgnK+Zvoi2Er1S3jU/y+ZgCGMA+A7Hdug==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>
+    <!--
     <script type="text/javascript" src="https://cdn.ethers.io/lib/ethers-5.4.umd.min.js"></script>
+    -->
     <script type="text/javascript" src="/static/help.js"></script>
     <script type="text/javascript" src="/static/script.js"></script>
   </body>

playground/sandbox.js

@@ -1,4 +1,5 @@
-importScripts("https:/\/cdn.ethers.io/lib/ethers-5.4.umd.min.js");
+//importScripts("https:/\/cdn.ethers.io/lib/ethers-5.4.umd.min.js");
+importScripts("https:/\/cdnjs.cloudflare.com/ajax/libs/ethers/5.6.4/ethers.umd.min.js");
 importScripts("./inspect.js");
 importScripts("./help.js");