Add client

Author: barryvdh

composer.json

@@ -46,6 +46,7 @@
         "php-http/client-implementation": "^1",
         "php-http/message": "^1.5",
         "php-http/discovery": "^1.2.1",
+        "php-http/guzzle7-adapter": "^0.1",
         "symfony/http-foundation": "^2.1|^3|^4|^5",
         "moneyphp/money": "^3.1"
     },