remove unneeded dependency

Author: ADmad

composer.json

@@ -30,7 +30,6 @@
     "require-dev": {
         "cakephp/cakephp-codesniffer": "^5.0",
         "cakephp/debug_kit": "^5.0",
-        "cakephp/plugin-installer": "^1.3",
         "michelf/php-markdown": "^1.9",
         "mikey179/vfsstream": "^1.6.10",
         "phpunit/phpunit": "^10.5.5 || ^11.1.3"