minor: fix test deprecations

Author: kbond

composer.json

@@ -15,7 +15,7 @@
     },
     "require-dev": {
         "phpstan/phpstan": "^1.4",
-        "phpunit/phpunit": "^9.5.0",
+        "phpunit/phpunit": "^9.6.19",
         "symfony/phpunit-bridge": "^6.1",
         "symfony/service-contracts": "^1.0|^2.0|^3.0",
         "symfony/var-dumper": "^5.4|^6.0"