Clarify mandatory sync configuration for NGINXaaS OIDC integration (#99)

Author: happyhd

README.md

@@ -209,7 +209,7 @@ Each of the `keyval_zone` parameters are described below.
 
   * **timeout** - Expired tokens are removed from the key-value store after the `timeout` value. This should be set to value slightly longer than the JWT validity period. JWT validation occurs on each request, and will fail when the expiry date (`exp` claim) has elapsed. If JWTs are issued without an `exp` claim then set `timeout` to the desired session duration. If JWTs are issued with a range of validity periods then set `timeout` to exceed the longest period.
 
-  * **sync** (optional) - If deployed in a cluster, the key-value store may be synchronized across all instances in the cluster, so that all instances are able to create and validate authenticated sessions. Each instance must be configured to participate in state sharing with the [zone_sync module](http://nginx.org/en/docs/stream/ngx_stream_zone_sync_module.html) and by adding the `sync` parameter to the `keyval_zone` directives above.
+  * **sync** (optional) - If deployed in a cluster, the key-value store may be synchronized across all instances in the cluster, so that all instances are able to create and validate authenticated sessions. Each instance must be configured to participate in state sharing with the [zone_sync module](http://nginx.org/en/docs/stream/ngx_stream_zone_sync_module.html) and by adding the `sync` parameter to the `keyval_zone` directives above. If deployed in [NGINXaaS for Azure](https://docs.nginx.com/nginxaas/azure/overview/overview/), **sync** is a must configuration. Check [NGINXaaS OIDC](https://docs.nginx.com/nginxaas/azure/quickstart/security-controls/oidc/) for more details.
 
 ## Session Management