Added cloudwatch example to aws4 readme

[sqdk]

Hi,

It took some time to get Cloudwatch to work, so i figured i would add an example here.

This procedure should (in theory) work with most services that are not as simple as S3 is.

I added a little comment that the library could probably help build the path string instead of having to do this explicitly. I find the code very hard to read and understand, so i choose not to undertake this.

Hopefully the discoveries can be of use for others :)

Cheers,
Christian @ Trustpilot

[heitortsergent]

Thanks so much for the PR @sqdk, that's super helpful! I agree with you that we could add a method to the lib to build out the path, I'm going to open an issue so we don't forget to do it.