Need to update use of load_plugin_textdomain

On line 111 of pingdom-rum.php you need to change the line to read:

load_plugin_textdomain('pingdom-rum', false, dirname(plugin_basename(__FILE__)) . '/i18n');

Notice the first parameter is now false.

This gets rid of a deprecated warning that’s existed since 2.7.

https://wordpress.org/plugins/real-user-monitoring-by-pingdom/