Split paginated roles and access requests

Access requests will be released in 15.2, roles will follow in 15.3.

docs/pages/upcoming-releases.mdx

@@ -14,14 +14,13 @@ The Teleport team delivers a new major release roughly every 4 months.
 
 ### 15.2.0
 
-TODO(zmb3)
-#### New paginated APIs
+#### Improved Access Requests UI
 
-Teleport's gRPC server will expose new paginated APIs for listing roles and
-access requests, which will improve performance on clusters with large numbers
-of these resources.
+The access requests page of the web UI will be backed by a paginated API,
+ensuring fast load times even on clusters with many access requests.
 
-*Delayed from Teleport 15.1.0*
+Additionally, the UI allows you to search for access requests, sort them
+based on various attributes, and includes several new filtering options.
 
 #### Zero-downtime web asset rollout
 
@@ -64,6 +63,15 @@ Kubernetes Operator.
 Users submitting access requests via web UI will be able to request specific
 access start time up to a week in advance.
 
+### 15.3.0
+
+#### Improved Roles UI
+
+The Roles page of the web UI will be backed by a paginated API, ensuring fast
+load times even on clusters with large numbers of roles.
+
+*Delayed from Teleport 15.1.0*
+
 ### 16.0.0
 
 #### Teleport VNet