Correct ladybug_set to ladybug_set_option

I have detect that when I set config parameters in config.yml show this error:

FatalErrorException: Error: Call to undefined function RaulFraile\Bundle\LadybugBundle\DependencyInjection\ladybug_set() in /Users/jl/php_projects/responsive/vendor/raulfraile/ladybug-bundle/RaulFraile/Bundle/LadybugBundle/DependencyInjection/RaulFraileLadybugExtension.php line 28

For this reason I have changed the ladybug_set() at line 28 by ladybug_set_options()

Thanks for this great tool.