Allow Guzzle 7.

Author: ash123456789

composer.json

@@ -7,7 +7,7 @@
     "license": "LGPL-3.0-only",
     "require": {
         "php": "^7.1",
-        "guzzlehttp/guzzle": "~6.0",
+        "guzzlehttp/guzzle": "^6.0 || ^7.0",
         "fzaninotto/faker": "^1.6",
         "ext-json": "*"
     },