title: net core 2.2 to 3.0 authentication migration AddOpenIdConnect
body: <p>Currently I'm in upgrading asp net core 2.2 web site to net core 3.0 that uses Identity Server 4 authentication and found issue that stops me to finish this task: In .net core 3.0 there is no <strong>AddOpenIdConnect</strong> method in <strong>OpenIdConnectExtensions</strong> (docs are clear about it: </p>
  
  <p><a href="https://docs.microsoft.com/en-us/dotnet/api/microsoft.extensions.dependencyinjection.openidconnectextensions.addopenidconnect?view=aspnetcore-2.2&amp;viewFallbackFrom=aspnetcore-3.0)." rel="noreferrer">Link</a></p>
  
  <p>So is there any substitute in .net core 3.0? </p>
  
  <p>Startup.cs that works in net core 2.2</p>
  
  <pre><code>IServiceProvider ConfigureServices(IServiceCollection services)
  {    
      services.AddAuthentication(options =&gt;
                      {
                          options.DefaultScheme = CookieAuthenticationDefaults.AuthenticationScheme;
                      })
                      .AddCookie(options =&gt;
                      {
                          options.SlidingExpiration = true;
                          options.ExpireTimeSpan = TimeSpan.FromMinutes(60);
                      })
                      .AddOpenIdConnect("oidc", options =&gt;
                      {
                          options.SignInScheme = CookieAuthenticationDefaults.AuthenticationScheme;
  
                          options.Authority = "sso url";
                          options.RequireHttpsMetadata = false;
  
                          options.ClientId = "client_id";
                          options.ClientSecret = "secret";
                          options.ResponseType = $"{OpenIdConnectParameterNames.Code} {OpenIdConnectParameterNames.IdToken}";
  
                          options.SaveTokens = true;
                          options.GetClaimsFromUserInfoEndpoint = true;                    
                      })
  </code></pre>