Add version information

[dit7ya]

Thanks again for this project.

I would like to package this for NixOS. Could you please add version information and/or tagged releases?

Relevant: #10.

[06kellyjac]

You could add it as unstable-2022-02-09 with rev 64347899f5c60ccc3a7c5ebfa193364b918a38ef but yeah it could benefit from a release, more frequent go lib updates, etc before packaging

[tboerger]

If we just get a git tag iot would already help to properly version an overlay for NixOS and we don't need to come up with some version scheme on our own.