Set minimium php version for phpcf

Author: sascha-egerer

phpcs.xml

@@ -5,6 +5,8 @@
 	<arg name="encoding" value="utf-8"/>
 	<arg name="tab-width" value="4"/>
 	<arg value="sp"/>
+	<config name="php_version" value="70400"/>
+
 	<file>src</file>
 	<file>tests</file>