Update PHPUnit to 9.5.5

Author: morozov

composer.json

@@ -42,7 +42,7 @@
         "doctrine/coding-standard": "9.0.0",
         "jetbrains/phpstorm-stubs": "2020.2",
         "phpstan/phpstan": "0.12.81",
-        "phpunit/phpunit": "^7.5.20|^8.5|9.5.0",
+        "phpunit/phpunit": "^7.5.20|^8.5|9.5.5",
         "squizlabs/php_codesniffer": "3.6.0",
         "symfony/cache": "^4.4",
         "symfony/console": "^2.0.5|^3.0|^4.0|^5.0",