Adds EOL banner for RHACS 3.73 docs

Author: gaurav-nelson

_templates/_page_openshift.html.erb

@@ -43,7 +43,7 @@
   <%
     unsupported_versions = ["3.0", "3.1", "3.2", "3.3", "3.4", "3.5", "3.6", "3.7", "3.9", "3.10", "4.1", "4.2", "4.3", "4.4", "4.5", "4.6", "4.7", "4.8", "4.9"];
 
-    unsupported_versions_acs = ["3.65", "3.66", "3.67", "3.68", "3.69", "3.70", "3.71", "3.72"];
+    unsupported_versions_acs = ["3.65", "3.66", "3.67", "3.68", "3.69", "3.70", "3.71", "3.72", "3.73"];
 
     unsupported_versions_serverless = [];