chore(deps): update dependency wp-phpunit/wp-phpunit to ^6.9.0

Author: renovate[bot]

composer.json

@@ -79,7 +79,7 @@
 		"phpstan/phpstan-phpunit": "^1.4.2",
 		"slevomat/coding-standard": "^8.20.0",
 		"szepeviktor/phpstan-wordpress": "^1.3.5",
-		"wp-phpunit/wp-phpunit": "^6.8.2",
+		"wp-phpunit/wp-phpunit": "^6.9.0",
 		"yoast/phpunit-polyfills": "^4.0",
 		"phpstan/php-8-stubs": "^0.4.18",
 		"phpstan/phpstan-strict-rules": "^1.6.2",