DOCSP-33552 update doc with the Ops Manager 6.0 EOL date (#42)

- [DOCSP-33552](https://jira.mongodb.org/browse/DOCSP-33552)
-
[Stage](https://preview-mongodbkanchanamongodb.gatsbyjs.io/ops-manager/DOCSP-33552/)
-
[Build](https://workerpool-boxgs.mongodbstitch.com/pages/job.html?collName=queue&jobId=65a999768aeba96efb35b0ff)

Author: kanchana-mongodb

snooty.toml

@@ -272,3 +272,14 @@ vmg-full = "Virtual Machine Group"
 win-http-service = "MongoDB Ops Manager HTTP Service"
 xml = ":abbr:`XML (eXtensible Markup Language)`"
 yaml = ":abbr:`YAML (Yet Another Markup Language)`"
+
+[[banners]]
+
+# OM v6.0 Deprecation per DOCSP-33552
+targets = [
+        "*.txt"
+        ]
+variant = "warning"
+value = """\
+        Ops Manager v6.0 will EOL in January 2025. Upgrade to a higher Ops Manager version as soon as possible.
+        """