Merge pull request #2222 from gmponos/require_ext-json

Require ext-json

composer.json

@@ -22,6 +22,7 @@
     ],
     "require": {
         "php": ">=5.5",
+        "ext-json": "*",
         "guzzlehttp/promises": "^1.0",
         "guzzlehttp/psr7": "^1.4"
     },
@@ -33,6 +34,9 @@
     "suggest": {
         "psr/log": "Required for using the Log middleware"
     },
+    "config": {
+        "sort-packages": true
+    },
     "extra": {
         "branch-alias": {
             "dev-master": "6.3-dev"