Promises, promises #10
Description
the request module in use by this package was deprecated a long time ago and doesn't support promises. I want to give this package the ability to use both callbacks (for backward compatibility) and promises, which are more modern and easier to use. I've therefore swapped request for node-fetch but I'm running into an issue. perhaps you could help? it's not properly germane to this package but if I can get it solved I can modernise this package. I've posted the issue here: mhart/aws4#144