Merge pull request #420 from mrrobot47/update/guzzle

Update guzzlehttp to 6.5.8

Author: mrrobot47

composer.json

@@ -51,7 +51,7 @@
     "require": {
         "acmephp/core": "1.2.0",
         "ext-openssl": "*",
-        "guzzlehttp/guzzle": "6.3.3",
+        "guzzlehttp/guzzle": "6.5.8",
         "league/flysystem": "1.1.4",
         "symfony/serializer": "3.4.20",
         "webmozart/assert": "1.10.0",