We can not use discovery 0.6.0

Author: Nyholm

composer.json

@@ -15,7 +15,7 @@
     "prefer-stable": true,
     "require": {
         "php": ">=5.5",
-        "php-http/discovery": "^0.6",
+        "php-http/discovery": "^0.6.1",
         "php-http/client-implementation": "^1.0",
         "php-http/message-factory": "^1.0",
         "php-http/plugins": "dev-master",