Update guzzlehttp

[joedolson]

Reported via email:

Hello,

We have been testing your plugin wp-to-twitter.

It contains an outdated "guzzlehttp" plugin that is conflicting with other plugins that use it.
To resolve it, in our local copy of tp-to-twitter, we updated the "vendor_prefixed/vendor/guzzlehttp" with an updated version and our errors went away.

This conflicted with two plugins we are using: "newsletter-amazon" and "ad-inserter".

Please review your plugin and update the vendor files.

Cheers,

Ash