Try widening PHPUnit versions even further so that we can attempt to test on older versions of PHP

Author: Garethp

composer.json

@@ -45,6 +45,6 @@
 		"mockery/mockery": "1.3.*",
 		"goetas/xsd2php": "2.1.*",
 		"goetas/xsd-reader": "2.0.x-dev",
-		"phpunit/phpunit": "11.*|10.*"
+		"phpunit/phpunit": "11.*|10.*|9.*"
 	}
 }