(DOCSP-30846) Adds deprecation banner to v1.23 docs (#820)

Author: sarahsimpers

snooty.toml

@@ -2,6 +2,13 @@ name = "mongocli"
 title = "MongoDB Command Line Interface"
 eol = true
 
+[[banners]]
+targets = ["*"]
+variant = "info"
+value = """\
+    This version of the documentation is archived and no longer supported. View the current documentation[https://www.mongodb.com/docs/mongocli/stable/] to learn how to upgrade[https://www.mongodb.com/docs/mongocli/stable/install/#update-the-mongodb-cli] your version of MongoCLI.\
+    """
+
 intersphinx = [ "https://www.mongodb.com/docs/ops-manager/current/objects.inv",            
                 "https://www.mongodb.com/docs/manual/objects.inv",
                 "https://www.mongodb.com/docs/atlas/objects.inv",