Upload to hackage automatically

[turion]

Ideally, the CI would publish to hackage, using https://github.com/haskell-actions/hackage-publish. I'm a bit unsure what the ideal conditions would be. I guess something like:

• Only on branches matching release*
• Only if cabal check doesn't throw warnings
• Only if approved by a maintainer with write access, or rather only when merged into master
• Only on tags matching v*.*.* with the corresponding version number

@ners you said you wanted to look into this, can I assign to you?

[ners]

@turion please do, I'll have some time to look into it in the coming days.