Merge pull request #12 from sj-i/renovate/phpunit-phpunit-9.x

Update dependency phpunit/phpunit to v9.5.9

Author: sj-i

composer.json

@@ -28,7 +28,7 @@
     "psr/log": "^1.1"
   },
   "require-dev": {
-    "phpunit/phpunit": "9.5",
+    "phpunit/phpunit": "9.5.9",
     "squizlabs/php_codesniffer": "3.6.0",
     "php-coveralls/php-coveralls": "2.4.3",
     "vimeo/psalm": "4.9.3",