Merge pull request #2 from proget-hq/guzzle7

Allow guzzle 7.x

Author: danieljonderko

composer.json

@@ -12,7 +12,7 @@
     ],
     "require": {
         "php": ">=5.6.3",
-        "guzzlehttp/guzzle": "^6.2",
+        "guzzlehttp/guzzle": "^6.2||^7.0",
         "symfony/polyfill-apcu": "^1.6"
     },
     "require-dev": {