Merge pull request #8 from curder/master

Update guzzlehttp/guzzle package support.

Author: calchen

composer.json

@@ -31,7 +31,7 @@
     "require": {
         "php": "^7.0",
         "ext-json": "*",
-        "guzzlehttp/guzzle": "^6.0",
+        "guzzlehttp/guzzle": "^6.3.1|^7.0.1",
         "illuminate/notifications": "^5.5|^6.0|^7.0|^8.0",
         "illuminate/support": "^5.5|^6.0|^7.0|^8.0"
     },