Update page.html

Author: alexellis

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@@ -27,7 +27,7 @@ <h2 class="subtitle is-size-4">
 	<section class="gumroad-cta">
 		<h3 class="gumroad-cta-title">Checkout the official eBook and video workshop for OpenFaaS</h3>
 			<a href="https://gumroad.com/l/serverless-for-everyone-else">
-			<img src="https://static-2.gumroad.com/res/gumroad/2028406193591/asset_previews/714aad765f8246463fafb64fcd3be4ea/retina/104810333-b628f280-57eb-11eb-8be9-a2f6c773346b.png" alt="Serverless eBook cover">
+			<img src="https://static-2.gumroad.com/res/gumroad/2028406193591/asset_previews/741f2ad46ff0a08e16aaf48d21810ba7/retina/social4.png" alt="Serverless eBook cover">
 			</a>
 			<p>Learn use-cases for open-source serverless functions and how to integrate them into your existing workflows.</p>
 			<p>Through the hands-on exercises you will build your own JavaScript functions using Node.js. You'll add custom npm modules, integrate with other HTTP APIs, enable authentication and monitor the endpoints with Grafana.</p>