fix(frankenphp-symfony): add Symfony 8 to composer constraints

PR php-runtime#185 ("Update Symfony package versions to include 8.0") updated the
Symfony constraints for all other packages in this mono-repo but missed
frankenphp-symfony — only the PHPUnit dev-dependency was bumped.

The runtime uses stable Symfony interfaces (HttpKernelInterface,
TerminableInterface, RunnerInterface, SymfonyRuntime) that are unchanged
in Symfony 8.0, so no code changes are required.

Author: dennismenken

src/frankenphp-symfony/composer.json

@@ -11,9 +11,9 @@
     ],
     "require": {
         "php": ">=8.1",
-        "symfony/dependency-injection": "^5.4 || ^6.0 || ^7.0",
-        "symfony/http-kernel": "^5.4 || ^6.0 || ^7.0",
-        "symfony/runtime": "^5.4 || ^6.0 || ^7.0"
+        "symfony/dependency-injection": "^5.4 || ^6.0 || ^7.0 || ^8.0",
+        "symfony/http-kernel": "^5.4 || ^6.0 || ^7.0 || ^8.0",
+        "symfony/runtime": "^5.4 || ^6.0 || ^7.0 || ^8.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^10.5.58"