fix: patch config.js to remove duplicate values

Author: darcyclarke

lib/utils/config.js

@@ -231,8 +231,6 @@ const types = {
   global: Boolean,
   'global-style': Boolean,
   globalconfig: path,
-  'https-proxy': [null, url],
-  'user-agent': String,
   heading: String,
   'https-proxy': [null, url],
   'if-present': Boolean,