No option to convert the Feed XML to JSON_LISTINGS_FEED

[immanuelt]

Amazon going to deprecate Feed XML API soon.
Do you have any updated version?
https://developer-docs.amazon.com/sp-api/changelog/deprecation-of-feeds-api-support-for-xml-and-flat-file-listings-feeds

[huntmj01]

@immanuelt

The amazonConnection.Feed.SubmitFeedAsync method currently works when using the JSON_LISTINGS_FEED. What doesn't work is the method to process the result (GetFeedDocumentProcessingReportAsync) which is only setup to handle an XML result.

I have opened a PR to add a method that can be used to parse the JSON_LISTINGS_FEED result.

My PR also includes in the README and in FeedsSample.cs an example of how to submit a price change using the JSON_LISTINGS_FEED.