You can get a self contained cli (jgit.sh) from here: https://eclipse.org/jgit/download/ . It does not have an eclipse dependency.
you can then just add an s3 remote and push to this remote as part of your CI flow.
Here is a decent article that describes the end-to-end: http://www.fancybeans.com/blog/2012/08/24/how-to-use-s3-as-a...