Docs: update availability notice for sso keycloak group sync

## What

This change updates the availability notice in the SSO keycloak setup
guide.

## Why

Because the notice still said that it's an "upcoming" feature, but it
was released in 4.18.

website/docs/how-to/how-to-setup-sso-keycloak-group-sync.md

@@ -4,7 +4,7 @@ title: 'How to set up Keycloak and Unleash to sync user groups'
 
 :::info availability
 
-User group syncing is an upcoming Unleash feature that will be available for enterprise customers.
+User group syncing was released in Unleash 4.18 and is available to enterprise customers.
 
 :::