Merge pull request #66141 from CarmiWisemon/oadp2664upgrade

Author: adellape

modules/about-oadp-update-channels.adoc

@@ -19,6 +19,8 @@ The following update channels are available:
 
 * The *stable-1.2* channel contains `oadp.v1.2._z_`, the most recent OADP 1.2 `ClusterServiceVersion`.
 
+* The *stable-1.3* channel contains `oadp.v1.3._z_`, the most recent OADP 1.3 `ClusterServiceVersion`.
+
 *Which update channel is right for you?*
 
 * The *stable* channel is now deprecated.  If you are already using the stable channel, you will continue to get updates from `oadp.v1.1._z_`.