build git-annex releases with minting a release and uploading builds as its assets

[yarikoptic]

build artifacts disappear from github after some time (30? days or so). We haven't yet established automated archival of all builds (#2). @vsoch 's (ab)use of github actions to build singularity containers (https://github.com/singularityhub/singularity-deploy) and uploading them as release assets gave me this now obvious idea that we can orchestrate distribution of builds directly here. I think it would work nicely for us here: file size limit imposed by github is 2GB and otherwise there seems to be no limits (on number of files or bandwidth) ATM: https://docs.github.com/en/github/administering-a-repository/about-releases

ATM we do not mint github releases here, and have just a collection of the tags. I guess we need to

• trigger a build for a new release of git-annex (if not yet build/released I guess; and we have already a script to help dispatching those)
• after success build, generate a fresh release and upload all built there artifacts as release asset

[vsoch]

Sounds like a great idea! You can pretty much copy the GitHub workflow in that linked repository verbatim - it does exactly almost what you describe (of course with a little tweaking to be specific to git-annex, and probably the files you want to save).