added UploadResponse support for UploadFileAsync

[kunalshetye]

The UploadFileAsync method does not return any mediaId of the asset that was uploaded so added UploadFileAsync model to return that information

[coveralls]

Coverage decreased (-0.4%) to 46.613% when pulling a140e4d on kunalshetye:feature/add-uploadfile-response into 7810cb0 on Bynder:master.

[githuib]

Thanks for your pull request. It makes a lot of sense and we actually added a very similar thing to our next big release that is planned to come out soon. The code can be seen here: https://github.com/Bynder/bynder-c-sharp-sdk/tree/FS_upload_dev

On the one hand I think it would be good to have such a change in the current release, but a problem I could see is it will change the return type of AssetService.UploadFileAsync(), therefore breaking the existing API, which could be a problem for some users of the SDK.
The new major release will have several breaking changes, so that's why we did include it there.

For the time being waiting on that major release, what we could consider is adding it as a new method instead of changing the existing one, so it would solve your issue while not breaking the API for other users.

I'll come back at this when we made a decision about this.

[kunalshetye]

Already implemented in https://github.com/Bynder/bynder-c-sharp-sdk/tree/FS_upload_dev