Update phpunit

Author: donatj

composer.json

@@ -6,7 +6,7 @@
 		"php": ">=7.4"
 	},
 	"require-dev": {
-		"phpunit/phpunit": "~7.5 | ~9.5",
+		"phpunit/phpunit": "~8.5 | ~9.5",
 		"squizlabs/php_codesniffer": "^3.5",
 		"corpus/coding-standard": "~0.6.0",
 		"friendsofphp/php-cs-fixer": "^2.17",