[helm chart]adding disable keyrenewperiod comment (#1455)

adding disable keyrenewperiod comment in helm values file, as without
quotes it wont work.

very minor adjustment to helm chart values file (just adding a comment)
to prevent wondering why it doesnt get picked up.

Signed-off-by: Mans Matulewicz <cybermans@gmail.com>

helm/sealed-secrets/values.yaml

@@ -74,6 +74,7 @@ skipRecreate: false
 ## @param keyrenewperiod Specifies key renewal period. Default 30 days
 ## e.g
 ## keyrenewperiod: "720h30m"
+## To disable use "0", with quotes!
 ##
 keyrenewperiod: ""
 ## @param rateLimit Number of allowed sustained request per second for verify endpoint