Add a section about request caching in the 2.x -> 3.x migration guide

guide/migration/20-to-30.md

@@ -98,6 +98,20 @@ services.AddOpenIddict()
     });
 ```
 
+## Enable request caching
+
+If previously application was using request caching functionality, the new way to toggle request caching feature (previously `options.EnableRequestCaching()`) to use `OpenIddictServerAspNetCoreBuilder` class  methods (divided into explicit methods):
+
+```csharp
+services.AddOpenIddict()
+    .AddServer(options =>
+    {
+        options.UseAspNetCore()
+            .EnableAuthorizationRequestCaching()
+            .EnableLogoutRequestCaching();
+    })
+```
+
 ## Replace JSON.NET by `System.Text.Json`
 
 If you use JSON.NET to serialize or deserialize `OpenIdConnectMessage`, `OpenIdConnectRequest` or `OpenIdConnectResponse` instances,