Update ruleset.xml

Removes default arguments given to phpcs. See #5. This allows for more customization or manually passing preferred arguments to phpcs. This is kind of a breaking change because the default behavior changes. To run phpcs with the same arguments before version ^2.0 of this package, run:

php vendor/bin/phpcs -spvnl --standard=phpcs-laravel <files / directories>

ruleset.xml

@@ -105,7 +105,6 @@
     <exclude-pattern>*/Providers/*</exclude-pattern>
 
     <arg name="colors"/>
-    <arg value="spvnl"/>
     <ini name="memory_limit" value="128M"/>
 
     <rule ref="PSR2"/>