Update content/vault/global/partials/policies/list-allowed-parameters.mdx

Co-authored-by: Sarah Chavis <62406755+schavis@users.noreply.github.com>

Author: bosouza

content/vault/global/partials/policies/list-allowed-parameters.mdx

@@ -30,4 +30,10 @@ parameters as lists when evaluating `allowed_parameters` and `denied_parameters`
 For instance, configuring `denied_parameters` as `"Z": ["C", "D", ["C"], ["D"], ["C", "D"], ["D", "C"]]`
 does not block requests that set `"Z": "C,D"` or `"Z": "D,C"`
 
-Vault 1.21.0 and later corrects all of these unexpected behaviors.
+<Tip title="Consider upgrading to 1.21.x or later">
+
+Vault addressed the unexpected behavior of
+`allowed_parameters` and `denied_parameters` in 1.21.x with
+more intuitive list processing.
+
+</Tip>