Rewrite action with github-script

[brandonchinn178]

Javascript is much better than bash, with proper error mechanisms, better variables, better for-loops, etc. This also lets us use all the utilities normal GitHub actions can use, via actions/github-script, taking advantage of the whole ecosystem.

Also changed input publish to candidate because it feels weird to say "run hackage-publish but don't publish".

Tested here: https://github.com/fourmolu/fourmolu/actions/runs/4624388970/jobs/8203029673

[brandonchinn178]

@AlexeyRaga Is this package still maintained? If not, I'd be happy to take over.

[jamesdbrock]

What are the functional advantages of this PR @brandonchinn178 ? How does it behave better than the bash-based action?

[brandonchinn178]

Three concrete functional advantages from just a quick skim of the bash code:

• What if packagesPath contains a space? The find command will output a space and the for loop would iterate on them as separate files
• What if the find command fails for some ephemeral reason? The for loop would iterate on an empty string and immediately return successfully
• What if the curl command for HACKAGE_STATUS failed without getting a status? Maybe the package doesnt exist, but the network is flaky, causing HACKAGE_STATUS to be an empty string instead of 404, and then the script does something

Sure, maybe these arent terrible issues, and maybe the script is small enough to be easy to debug or whatever. But bash has so many small edge cases that can bite you later.