Update link to the OpenShift Security Guide

Resolves #54189

Author: reftel

security/container_security/security-understanding.adoc

@@ -65,4 +65,4 @@ include::modules/security-understanding-openshift.adoc[leveloffset=+1]
 [role="_additional-resources"]
 .Additional resources
 * xref:../../architecture/architecture.adoc#architecture[{product-title} architecture]
-* link:https://access.redhat.com/articles/5059881[OpenShift Security Guide]
+* link:https://www.redhat.com/en/resources/openshift-security-guide-ebook[OpenShift Security Guide]