Fix deprecated exceptions guzzle request option

[deguif]

This was deprecated in 6.0 version and a http_errors was introduced at this time. This won't work anymore with guzzle 7.x as exceptions option was removed.

[deguif]

By the way I'm not sure which guzzle\guzzle versions are supported. It seems it's only 6.x currently.
@ruflin can you confirm?

[deguif]

@ruflin should now be ready to merge.

[ruflin]

@deguif PR LGTM. For the guzzle question, TBH not sure. Why do you mean exactly by "supported"?

[deguif]

By supported I mean the minimal version which works with ruflin/elastica when using guzzle transport shipped there.

[ruflin]

Good question, we haven't discuss this TBH. We should probably specify it?

[deguif]

A hard composer requirement would probably not be a good choice.
But adding a conflict could work, but can be sources of issues, as using ruflin/elastica doesn't mean you will use its guzzle transport.
Or at least check at runtime when using the guzzle transport, that would be the less intrusive solution.

[deguif]

@ruflin I think this can be merged. The point about minimum version of guzzle/guzzle supported can be addressed in a future PR. Currently it seems it supports v6 and upper, but it needs some adaptations for v7 ;)