chore(deps): update dependency phpunit/phpunit to v9.1.4

Author: renovate-bot

composer.json

@@ -22,7 +22,7 @@
     "minimum-stability": "stable",
     "require": {},
     "require-dev": {
-        "phpunit/phpunit": "9.0.1"
+        "phpunit/phpunit": "9.1.4"
     },
     "scripts": {
         "test": "phpunit --coverage-text"