Fix Guzzle requirement

[dunglas]

guzzle/http is abandoned. This PR use the new Composer package guzzle/guzzle. It avoid the following errors when installing the bundle:

Package guzzle/common is abandoned, you should avoid using it. Use guzzle/guzzle instead.
Package guzzle/stream is abandoned, you should avoid using it. Use guzzle/guzzle instead.
Package guzzle/parser is abandoned, you should avoid using it. Use guzzle/guzzle instead.
Package guzzle/http is abandoned, you should avoid using it. Use guzzle/guzzle instead.

fix #176

[dbu]

we do not really need all the other things of guzzle, but i guess we have to change when guzzle is no longer updating those subtree splits. @ddeboer do you agree?

the situation will improve with #173 btw, when we do not need to depend on a specific client anymore.

[carlcraig]

👍

[dbu]

ping @ddeboer

[ddeboer]

Thanks, @dunglas!

[ddeboer]

And tagged 1.3.1.