Add ext-json

Author: odan

composer.json

@@ -14,7 +14,8 @@
     "require": {
         "php": "^7.2 || ^8.0",
         "psr/http-factory": "^1.0.1",
-        "psr/http-server-middleware": "^1.0.1"
+        "psr/http-server-middleware": "^1.0.1",
+        "ext-json": "*"
     },
     "require-dev": {
         "fig/http-message-util": "^1.1",