Render the XML XSD of the phpunit that is installed on the project (#440)

Author: srtfisher

phpunit.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <phpunit
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-  xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.5/phpunit.xsd"
+  xsi:noNamespaceSchemaLocation="./vendor/phpunit/phpunit/phpunit.xsd"
   bootstrap="tests/bootstrap.php"
   backupGlobals="false"
   colors="true"