Allow guzzlehttp/guzzle 7.2 version

[deguif]

Support guzzlehttp/guzzle:7.2 as that's where PHP 8.0 support was added.
It requires some work:

• Fix deprecated option not available anymore [Fix deprecated exceptions guzzle request option #1817]
• Fix ConnectException extending TransferException now instead of RequestException [Fix Guzzle ConnectException inheritance change #1825]

[ruflin]

Will your other guzzle PR fix the current CI issues?

[deguif]

Yes I will make PRs to fix the issues raised here and rebase this one once they get merged.
#1817 is one of them.
There is a second I will have to do as ConnectException inherits now TransferException instead of RequestException, and some tests are relying on RequestException to do some assertions.

[ruflin]

In general LGTM as soon as CI passes. Probably worth to add a cahngelog entry.