chore(deps): update dependency phpunit/phpunit to v9.3.9

Author: renovate-bot

composer.json

@@ -12,7 +12,7 @@
   "require": {},
   "require-dev": {
     "codedungeon/phpunit-result-printer": "0.28.0",
-    "phpunit/phpunit": "9.3.8",
+    "phpunit/phpunit": "9.3.9",
     "spatie/phpunit-watcher": "1.22.0"
   },
   "autoload": {