Fix version number in upgrade readme to 4.0.

playbooks/byo/openshift-cluster/upgrades/README.md

@@ -4,4 +4,4 @@ cluster. Additional notes for the associated upgrade playbooks are
 provided in their respective directories.
 
 # Upgrades available
-- [OpenShift Container Platform 3.11 to 4.0](v4_0/README.md) (upgrade OpenShift Origin from 3.10.x to 3.11.x)
+- [OpenShift Container Platform 3.11 to 4.0](v4_0/README.md) (upgrade OpenShift Origin from 3.11.x to 4.0.x)