Introduce support to return 201 status code in Json Responses

[denjaland]

While refactoring our existing code from Laravel API resources to using Laravel Data, we noticed a lot of our tests were starting to fail, because we expect a 201 CREATED response code when we are creating a new resource.

I checked the Laravel codebase, and they return a 201 when $model->wasRecentlyCreated() equals true.
Obviously, the same check can not be done in this package, but I believe it would make sense to test for the request method, and if it is a POST request, we can have return the Json response with a 201 status code, which is what I implemented in this PR.

Obviously, in order to ensure backwards compatibility, I disabled this by default by adding a new config parameter that is y default set to false, but can be enabled in the config file, so this can be release as a minor and not a major.

[rubenvanassche]

Hi @denjaland,

Thanks for the PR, I think this is more of a bugfix. So let's skip the whole config flag and do this by default! Could you make these changes? Thanks!

[denjaland]

Will do. I'm always careful making backwards incompatible changes, but I agree it's a fix.

[denjaland]

@rubenvanassche updated PR