Add banner for agentv2 documentation (#1481)

* Add banner for agentv2 documentation

* Update _banners/agent-v2-note.md

Co-authored-by: Alan Dooley <a.dooley@f5.com>

* Update _banners/agent-v2-note.md

Co-authored-by: Alan Dooley <a.dooley@f5.com>

---------

Co-authored-by: Jon Torre <78599298+JTorreG@users.noreply.github.com>
Co-authored-by: Alan Dooley <a.dooley@f5.com>

Author: 3 people

_banners/agent-v2-note.md

@@ -0,0 +1,5 @@
+{{< banner "notice" "You are viewing NGINX Agent version 2 documentation" >}}
+This set of documentation is for **NGINX Agent version 2.x**. 
+
+For NGINX Agent 3.x content visit the [NGINX One Console documentation]({{< ref "/nginx-one-console/agent/overview/about/" >}})
+{{< /banner >}}

content/agent/_index.md

@@ -7,8 +7,8 @@ cascade:
     enabled: true
     type: deprecation
     start-date: 2025-05-29
-    end-date: 2025-09-09
-    md: /_banners/agent-v3-release.md
+    end-date: 2026-09-09
+    md: /_banners/agent-v2-note.md
 # The subtitle displays directly underneath the heading of a given page
 nd-subtitle:
 # Indicates that this is a custom landing page