update: use Racks request.params[] instead of Request#[]

the latter is deprecated and will be removed eventually.

lib/omniauth/strategies/sso.rb

@@ -38,7 +38,7 @@ module OmniAuth
       end
 
       def info_from_ticket
-        @info_from_ticket ||= client.open request["t"]
+        @info_from_ticket ||= client.open request.params["t"]
       end
 
       def client