Require Tester with PHP 8.5 support

Otherwise --prefer-lowest tests fail on 8.5.

Author: spaze

composer.json

@@ -18,7 +18,7 @@
 		"php-parallel-lint/php-console-highlighter": "^1.0",
 		"phpstan/phpstan": "^2.1",
 		"spaze/coding-standard": "^1.8",
-		"nette/tester": "^2.4"
+		"nette/tester": "^2.5.7"
 	},
 	"autoload": {
 		"psr-4": {