Link to local XSD (#3218)

This will allow IDEs to provide hints/ autocompletion

Author: BackEndTea

phpunit.xml.dist

@@ -2,7 +2,7 @@
 
 <!-- http://phpunit.de/manual/4.1/en/appendixes.configuration.html -->
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/4.6/phpunit.xsd"
+         xsi:noNamespaceSchemaLocation="./vendor/phpunit/phpunit/phpunit.xsd"
          backupGlobals="false"
          bootstrap="tests/Fixtures/app/bootstrap.php"
          colors="true"