Update import path for FEAScript library

Author: nikoscham

tutorials/heat-conduction-2d-fin-worker.html

@@ -161,7 +161,7 @@ <h2 id="webworkerimplementation"><a name="Web Worker Implementation"></a>Web Wor
   &lt;!-- ...body region... --&gt;
   &lt;script type="module"&gt;
     // Import FEAScript library
-    import { FEAScriptWorker, plotSolution, printVersion } from "https://core.feascript.com/dist/feascript.esm.js";
+    import { FEAScriptWorker, plotSolution, printVersion } from "https://core.feascript.com/src/index.js";
 
     window.addEventListener("DOMContentLoaded", async () =&gt; {
       // Print FEAScript version in the console