Update PHPUnit configuration

Author: sebastianbergmann

phpunit.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
-         bootstrap="vendor/autoload.php"
          cacheDirectory=".phpunit.cache"
          executionOrder="depends,defects"
          requireCoverageMetadata="true"