title: What is equivalent to `MapSpaFallbackRoute` for ASP.NET Core 3.0 endpoints?
body: <p>In ASP.NET Core 2.x I used standard routes registation <code>Configure</code> method of <code>Startup</code> class to <strong>register fallback route</strong> for SPA application using <code>MapSpaFallbackRoute</code> extension method from <code>Microsoft.AspNetCore.SpaServices.Extensions</code> Nuget package:</p>
  
  <pre class="lang-cs prettyprint-override"><code>public void Configure(IApplicationBuilder app)
  {
      // ...
      app.UseMvc(routes =&gt;
      {
          routes.MapRoute(
              name: "default",
              template: "{controller=Home}/{action=Index}/{id?}");
          routes.MapSpaFallbackRoute(
              name: "spa-fallback",
              defaults: new { controller = "Home", action = "Index" });
      });
  }
  </code></pre>
  
  <p>I cannot find similar extension method when using ASP.NET Core 3.0 recommended <code>UseEndpoints</code> extension method for endpoints registration.</p>