fix(composer): add missing json PHP extension requirement

Author: gaetan-hexadog

composer.json

@@ -15,6 +15,7 @@
     "minimum-stability": "stable",
     "require": {
         "php": ">=7.4",
+        "ext-json": "*",
         "hexadog/laravel-theme-installer": "^1.0",
         "illuminate/view": "^7.0|^8.0|^9.0|^10.0"
     },