Fix StreamableHTTPClientTransport instantiation

The baseUrl is type of URL at Line 1225.

Author: yuwzho

README.md

@@ -1228,9 +1228,7 @@ try {
     name: 'streamable-http-client',
     version: '1.0.0'
   });
-  const transport = new StreamableHTTPClientTransport(
-    new URL(baseUrl)
-  );
+  const transport = new StreamableHTTPClientTransport(baseUrl);
   await client.connect(transport);
   console.log("Connected using Streamable HTTP transport");
 } catch (error) {