Added support for Guzzle 7 and PHP 7.3-7.4

[GrahamCampbell]

I've also corrected your code style, most notably, a bunch of tabs instead of spaces, in some of the files. Additionally, you were missing a license file (composer.json indicated MIT), and repository field was miss-used in in composer.json file (fixed).

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NB This PR retains support for Guzzle 6 too, and also PHP 7.0-7.2. We end up with Guzzle 6 and 7 support, and PHP 7.0-7.4 support.

[GrahamCampbell]

Ping.

[jesperbjerke]

@atheken is anyone able to merge this pull request?

[GrahamCampbell]

Friendly ping @atheken. :)

[GrahamCampbell]

I suppose this package is dead. Someone should fork it to replace it.

[vladsandu]

@GrahamCampbell thank you for contributing to this library and we apologize for the great delay in getting to review this PR.

This looks good to me. Big thanks for fixing the coding style and working on the additional improvements.

If you are still interested in contributing, would it be possible to restore the deleted forked repository and re-create/re-open this PR? If possible, I would be more than happy to get this merged and released shortly after.

[mfn]

@vladsandu I took the liberty and created a … slightly smaller… PR ;) => #37

I totally understand @GrahamCampbell with all the changes in this PR, but let's take smaller steps, now that there's activity again.

[GrahamCampbell]

If someone else wants to take over from where I left off, feel free. I don't have time to do anything more, sorry.

[mfn]

@GrahamCampbell awesome and thanks for showing the way 🙏