Also add git sha to tag

[efrecon]

In order to make the difference between the source project and this project, we should consider:

• Generating tags such as 1.90-96052ad, i.e. combining the version from s3fs and the sha of the commit here.
• Generating tags as 1.90 corresponding to the latest build out of here.

This would allow external users to revert to images if modern additions broke things up.