Updating PHPUnit schema version.

Author: cyrilverloop

ci/phpunit.dist.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phpunit
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/12.3/phpunit.xsd"
+    xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/12.4/phpunit.xsd"
     bootstrap="../vendor/autoload.php"
     cacheDirectory="../var/cache/.phpunit.cache"
     colors="true"