Don't duplicate requests to charge or void payments

[Nebual]

Fixes #30

Both the charge() and voidChargeTransaction() methods are currently sending duplicate requests, and then ignoring the first response.

This seemingly wasn't a problem before (just would delay overall method time), however today the subsequent requests started returning empty responses (#30), which results in transactions going through that appear to have failed on the client's end. I'm guessing the API changed today to start checking the request-id or something as an idempotency key, and ignoring duplicates.

[Nebual]

If anyone else happens to be looking to do a Friday deploy to workaround this issue, add this to your "repositories" in composer.json:

  "repositories": [
    {
      "type": "vcs",
      "url": "https://github.com/Nebual/PHP-Payments-SDK.git"
    },
  ]

And then run:

composer require quickbooks/payments-sdk="dev-master#f6af73f85e412b7e87b8170c69c2647056641dfa"

That'll be release 1.0.8 + this PR's fix.

[brettgoss]

Hi @bsivalingam or @abisalehalliprasan - Since you both seem to have committed to this repository in the past, do you think you'd be able to approve and merge this pull request? It has been open for almost 3 years now, and will resolve issue #30.

It would be great if this issue could be resolved in this SDK so that we can stop pointing composer to @Nebual's fork.

[brettgoss]

I can't think of any valid reason why the SDK would need to explicitly send duplicate requests, so LGTM!

[mavelo-llc]

Is anyone actively maintaining this project? Submitted #42 a few days ago, then noticed this pull, pending for nearly 3 years 🤯