Doesn't allow for guzzle version 7.5

[mathmul]

guzzle release

[mathmul]

I have a PR ready, but no permissions to push.

The change is in composer.json LINE 31:

-        "guzzlehttp/guzzle": "^6.1 || ^7.0.1",
+        "guzzlehttp/guzzle": "^6.1 || ^7.0",