Remove unused development dependencies (#33)

Remove symfony/dependency-injection and symfony/event-dispatcher
from require-dev as they are not used in the codebase. The project
uses psr/event-dispatcher interface instead of symfony's implementation.

Author: OskarStark

composer.json

@@ -35,8 +35,6 @@
         "phpunit/phpunit": "^10.5",
         "psr/cache": "^3.0",
         "symfony/console": "^6.4 || ^7.0",
-        "symfony/dependency-injection": "^6.4 || ^7.0",
-        "symfony/event-dispatcher": "^6.4 || ^7.0",
         "symfony/process": "^6.4 || ^7.0"
     },
     "suggest": {