Introduce bang methods which raise exceptions when API returns errors

[vbyno]

e.g.: mws_api.subscriptions.register_destination!(...)

[main24]

Basically I believe there is no reason to keep both ways, i.e. when is it really necessary not to throw an exception if a request isn't successul?

[vbyno]

Basically I believe there is no reason to keep both ways, i.e. when is it really necessary not to throw an exception if a request isn't successul?

@main24, the first thing which comes to my mind is doing several requests in the loop, or several threads. For example,

results = feed_data_array.map { |feed_data| mws_api.feeds.submit_feed(feed_data) }
if results.all? { successful? }
   ...
else 
  ...
end

This would be much harder to process if we do it via catching exceptions.

Although, having error-based method a default one wouldn't be a bad idea. soft method could just be a flag (raise_error: false). Unfortunately, I'm not sure how this huge change in API could impact Veeqo app. It would require a rechecking the existing code and refactoring it.
Also, since the library is open-sourced, to follow the best practices, it would be nice to deprecate method in a new minor version. And replace it in a new major version (just to follow semantic versioning).
^ All of this will be needed if we decide to keep only "the strict" approach

[vbyno]

@main24 , I've added deprication warning to the regular methods. Please, take a look

[main24]

That's unrelated to the PR, please extract it into separate commit.

[main24]

Basically we're not going to get rid of methods without bang, but will change their behavior to the same as ones with bang – they'll be raising exceptions.