shared VPC what's new blurb

Author: aldiazRH

rosa_release_notes/rosa-release-notes.adoc

@@ -16,6 +16,8 @@ toc::[]
 [id="rosa-q3-2023_{context}"]
 === Q3 2023
 
+* **Shared virtual private clouds.** ROSA now supports installing clusters into VPCs shared among AWS accounts that are part of AWS organizations. AWS account installing ROSA cluster can now use shared subnets owned by a management account. For more information, see xref:../rosa_install_access_delete_clusters/rosa-shared-vpc-config.html[Configuring a shared virtual private cloud for ROSA clusters].
+
 * **ROSA CLI update:** The ROSA CLI (`rosa`) was updated to a new version. For information about what's changed in this release, see the link:https://github.com/openshift/rosa/releases/tag/v1.2.26[release notes]. For more information about the ROSA CLI (`rosa`), see xref:../cli_reference/rosa_cli/rosa-get-started-cli.adoc[Getting started with the ROSA CLI].
 
 * **ROSA regional availability update:** {product-title} (ROSA) is now available in the following regions: