fixes Payment struct AmountChargedBack json field tag

[arifmahmudrana]

Description

Update Payment struct AmountChargedBack json field tag from amountChargeback to amountChargedback and update the relevant documentation part

Motivation and context

While calling the Payment Get method it wasn't rightly populating the AmountChargedBack due to a wrong json field tag see #389

Fixes #389

How has this been tested?

Go unit tests were executed locally

Types of changes

What types of changes does your code introduce? Put an x in all the boxes that apply:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• This change requires a documentation update

Checklist

Go over all the following points, and put an x in all the boxes that apply.

Please, please, please, don't send your pull request until all of the boxes are ticked. Once your pull request is created, it will trigger a build on our continuous integration server to make sure your tests and code style pass.

• I have read the CONTRIBUTING document.
• My pull request addresses exactly one patch/feature.
• I have created a branch for this patch/feature.
• Each individual commit in the pull request is meaningful.
• If my change requires a change to the documentation, I have updated it accordingly.

[VictorAvelar]

Thanks for the quick fix. 🚀