Updated the index page to reflect correct EPAS version (#518)

Author: mpfuster

product_docs/docs/epas/18/index.mdx

@@ -2,7 +2,7 @@
 title: EDB Postgres Advanced Server (EPAS)
 navTitle: EDB Postgres Advanced Server
 directoryDefaults:
-  description: "EDB Postgres Advanced Server Version 17 documentation and release notes. Oracle database compatibility with higher security and data redaction for enterprises."
+  description: "EDB Postgres Advanced Server Version 18 documentation and release notes. Oracle database compatibility with higher security and data redaction for enterprises."
 navigation:
   - epas_rel_notes
   - epas_platform_support