Allow phpunit 9.x

Signed-off-by: William Desportes <[email protected]>

Author: williamdes

composer.json

@@ -26,7 +26,7 @@
         "phpstan/phpstan": "^0.12.3",
         "phpstan/phpstan-phpunit": "^0.12.1",
         "phpunit/php-code-coverage": "*",
-        "phpunit/phpunit": "^7.4 || ^8"
+        "phpunit/phpunit": "^7.4 || ^8 || ^9"
     },
     "conflict": {
         "phpmyadmin/motranslator": "<3.0"