Add guzzle 7.x support.

Author: HyanCat

composer.json

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