Add upgrade guide for previously deprecated beta fields (#5283)

mmv1/third_party/terraform/website/docs/guides/version_4_upgrade.html.markdown

@@ -15,6 +15,10 @@ description: |-
     - [Provider-level change example](#provider-level-change-example)
   - [Datasource: `google_product_resource`](#datasource-google_product_resource)
     - [Datasource-level change example](#datasource-level-change-example)
+- [Resource: `google_compute_instance_group_manager`](#resource-google_compute_instance_group_manager)
+    - [`update_policy.min_ready_sec` is removed from the GA provider](#update_policymin_ready_sec-is-removed-from-the-GA-provider)
+- [Resource: `google_compute_region_instance_group_manager`](#resource-google_compute_region_instance_group_manager)
+    - [`update_policy.min_ready_sec` is removed from the GA provider](#update_policymin_ready_sec-is-removed-from-the-GA-provider)
   - [Resource: `google_container_cluster`](#resource-google_container_cluster)
     - [`node_config.workload_metadata_config.node_metadata` is now removed](#node_configworkload_metadata_confignode_metadata-is-now-removed)
 
@@ -152,8 +156,32 @@ resource "google_runtimeconfig_config" "my-runtime-config" {
 
 Description of the change and how users should adjust their configuration (if needed).
 
+## Resource: `google_compute_instance_group_manager`
+
+### `update_policy.min_ready_sec` is removed from the GA provider
+
+This field was incorrectly included in the GA `google` provider in past releases.
+In order to continue to use the feature, add `provider = google-beta` to your
+resource definition.
+
+
+## Resource: `google_compute_region_instance_group_manager`
+
+### `update_policy.min_ready_sec` is removed from the GA provider
+
+This field was incorrectly included in the GA `google` provider in past releases.
+In order to continue to use the feature, add `provider = google-beta` to your
+resource definition.
+
+
 ## Resource: `google_container_cluster`
 
 ### `node_config.workload_metadata_config.node_metadata` is now removed
 
 Removed in favor of `node_config.workload_metadata_config.mode`.
+
+### `pod_security_policy_config` is removed from the GA provider
+
+This field was incorrectly included in the GA `google` provider in past releases.
+In order to continue to use the feature, add `provider = google-beta` to your
+resource definition.