docs: add section on changes from terraform-google-modules#1495

Author: mnahkies

docs/upgrading_to_v25.0.md

@@ -17,6 +17,26 @@ release.
 }
 ```
 
+### Use the created service account when creating autopilot clusters
+
+When `create_service_account` is `true` pass the created service account to the `cluster_autoscaling` -> `auto_provisioning_defaults` block
+for the `beta-autopilot-private-cluster` / `beta-autopilot-public-cluster` modules.
+
+This will mean that the `Nodes` will use the created service account, where previously the default service account was erronously used instead.
+
+To opt out, set `create_service_account` to `false`
+
+```diff
+  module "gke" {
+-   source           = "terraform-google-modules/kubernetes-engine"
+-   version          = "~> 24.0"
++   source           = "terraform-google-modules/kubernetes-engine"
++   version          = "~> 25.0"
+...
++   create_service_account  = false
+}
+```
+
 ### Minimum Google Provider versions
 
 Minimum Google Provider versions have been updated to `4.44.0`.