Update card title in Index.cshtml to reflect version change to v3

Author: CalinL

src/webapp01/Pages/Index.cshtml

@@ -6,7 +6,7 @@
 
 <div class="card text-center">
     <div class="card-body">
-        <h5 class="card-title">.NET 💜 Azure v2</h5>
+        <h5 class="card-title">.NET 💜 Azure v3</h5>
         <p class="card-text">Learn about <a href="https://learn.microsoft.com/aspnet/core">building Web apps with ASP.NET Core</a>.</p>
     </div>
 </div>