Update the progress when sync

[caueops]

Hello,

When my credentials do not have permissions for delete a object, the sync are showing the object are deleted but is wrong.

[pgherveou]

Yes this is because we are deleting all the files in bulk when the stream ends
https://github.com/pgherveou/gulp-awspublish/blob/master/lib/index.js#L390
We dont handle the error, I guess we should report it somehow to the user.
Feel free to send a PR if you want to implement that.