Please update dependencies for Lavavel 8

[dariocarbone]

Could you please update guzzlehttp/guzzle and illuminate/support dependencies in order to work with latest laravel v8 version?
Many thanks, your package is very simple and useful!!

[danielme85]

Hi, thank you for the heads-up.
Should not be restricted by composer dependency on the master branch now dc306e5
Not tested it in practice yet, but unit testing works for Guzzle 7 it seems.

[dariocarbone]

Thank you very much, I'll try to update on dev-master branch and find out if it's working, then look forward for next release