fix optional

Author: fe80

lib/puppet/functions/postgresql/postgresql_password.rb

@@ -21,7 +21,7 @@
     required_param 'Variant[String[1], Integer]', :username
     required_param 'Variant[String[1], Sensitive[String[1]], Integer]', :password
     optional_param 'Boolean', :sensitive
-    optional_param "Enum['md5', 'scram-sha-256']", :hash
+    optional_param "Optional[Enum['md5', 'scram-sha-256']]", :hash
     optional_param 'Optional[Variant[String[1], Integer]]', :salt
     return_type 'Variant[String, Sensitive[String]]'
   end