Move extension to the correct segment

Author: Bellangelo

composer.json

@@ -10,7 +10,6 @@
     "require": {
         "php": ">=7.4",
         "phpstan/phpstan": "^1.11",
-        "ext-json": "*"
     },
     "license": "Apache-2.0",
     "autoload": {
@@ -26,7 +25,8 @@
     ],
     "require-dev": {
         "squizlabs/php_codesniffer": "^3.10",
-        "phpunit/phpunit": "^9.6"
+        "phpunit/phpunit": "^9.6",
+        "ext-json": "*"
     },
     "scripts": {
         "phpcs": "./vendor/bin/phpcs --standard=PSR12 src tests",